Well I welcome all suggestions I want things to be how they were intended and I do like challenges but not to the point I die every 5 minutes or something.
Here is my load order, just updated to the latest FCOM today 0.9.9 believe it or not it fixed a ring I had oddly enough, there is a ring in the game shield ring you get during mages quest, it didn't have an enchantment before bugged obviously now, it has 6% about how I would expect it.
Actually after reviewing my difficulty slider was about 7 notches below half, so if this scale is a 100 mark scale, about 43 or something then, so a little low, and I actually knocked it up 2 notches during verona so I was probably using 41 during main quest
Basically when I fought mankar, I was wearing obsidian cuirass and greaves, using an elven shield, had 8% reflect damage, believe it was 6% reflect spell, think I was using one of the rings that boost skills 10 points for all the major spell groups, forget it's name now.   The scrolls I had believe I picked up laying around places, I have frostcrag reborn, so I may of gotten a couple from in there, there is a few very powerful items in it, but the armors and such it has that are overpowered I wasn't using and don't really intend to use, also have OMG, think I may of gotten a couple scrolls from place it adds. I started main quest around level 8, did fighter's guild, most of mages guild and knights before it, knowing FCOM was suppose to be harder I wanted to be higher level this time going in. Most of main quest was difficult enough, not intensive except the first time I met a daedric prince in the bruma gate, that got very close without some help from the guard captain I didn't have a chance. Paradise wasn't that tough at level 12 didn't seem like, but mankar himself was.  Xilval fury, just got unlucky I think, he attacked our group just as we exited the door, he got surrounded by 5 or so soldiers in the corner next to the door, since his focus wasn't on me or martin I could take a few swings to help make sure he didn't break through them all, he went down only due to be ganged up on, with little daedric help at that point since the other daedra hadn't gotten to us yet.
Just tested something today, turned up difficulty to truly half now, went to dark fissure, I met them once before during mages guild when I just waltzed in, they owned me when I was level 5 or 6, haven't faced one since, tried now at level 13 with difficulty higher. While I could take down 3 or 4 of them, they still owned me pretty good with damage health spells, without using my strongest health potions which I didn't try I couldn't keep enough health in, so it's obvious FCOM is working, as I'm seeing new enemies in the right places and difficulty seems higher than vanilla. Just think I need to keep that difficult slider up for sure as I think my skills have improved more than I've noticed as I kept it low before since I didn't play much of morrowind, so I came into oblivion a pure rookie almost.  
Active Mod Files:00  Oblivion.esm01  Francesco's Leveled Creatures-Items Mod.esm02  Francesco's Optional New Items Add-On.esm03  CM Partners.esm04  Cobl Main.esm  [Version 1.36]05  Oscuro's_Oblivion_Overhaul.esm  [Version 1.34Beta]06  Mart's Monster Mod.esm  [Version 3.6beta]07  FCOM_Convergence.esm  [Version 0.9.9a7]08  Cybiades.esm  [Version 2.0]**  TNR ALL RACES FINAL.esp**  TNR - ShiveringIsles.esp09  Unofficial Oblivion Patch.esp0A  Oblivion Citadel Door Fix.esp0B  DLCShiveringIsles.esp0C  Unofficial_Shivering_Isles_Patch_MOBS.esp0D  SM Plugin Refurbish - SI.esp  [Version 1.05]0E  Francesco's Optional Chance of Stronger Bosses.esp0F  Francesco's Optional Chance of Stronger Enemies.esp10  Francesco's Optional Leveled Guards.esp11  FCOM_Francescos.esp  [Version 0.9.9]12  FCOM_FrancescosItemsAddOn.esp  [Version 0.9.9]13  FCOM_FrancescosNamedBosses.esp  [Version 0.9.9]14  Fran Armor Add-on.esp15  Fran_Lv30Item_Maltz.esp16  nVidia Black Screen Fix.esp  [Version 1.0.0]17  Arthur_Natural_Weather_HDR_by_Max_Tael.esp18  IWR-Windows.esp19  Cities Alive At Night.esp1A  Reznod_Mannequin.esp1B  Living Economy.esp1C  Living Economy - Items.esp1D  Cutthroat Merchants.esp1E  Harvest [Flora].esp  [Version 3.0.0]1F  Harvest [Flora] - Shivering Isles.esp  [Version 3.0.0]20  DLCHorseArmor.esp21  DLCHorseArmor - Unofficial Patch.esp  [Version 1.0.2]22  SM Plugin Refurbish - HorseArmor.esp  [Version 1.08]23  DLCOrrery.esp24  DLCOrrery - Unofficial Patch.esp  [Version 1.0.2]25  SM Plugin Refurbish - Orrery.esp  [Version 1.06]26  DLCBattlehornCastle.esp27  DLCBattlehornCastle - Unofficial Patch.esp  [Version 1.0.1]28  SM Plugin Refurbish - Battlehorn.esp  [Version 1.06]29  DLCThievesDen.esp2A  DLCThievesDen - Unofficial Patch.esp  [Version 1.0.3]2B  DLCThievesDen - Unofficial Patch - SSSB.esp  [Version 1.0.2]2C  SM Plugin Refurbish - ThievesDen.esp  [Version 1.08]2D  DLCVileLair.esp2E  DLCVileLair - Unofficial Patch.esp  [Version 1.0.2]2F  Harvest [Flora] - DLCVileLair.esp  [Version 3.0.0]30  SM Plugin Refurbish - VileLair.esp  [Version 1.08]31  DLCMehrunesRazor.esp32  DLCMehrunesRazor - Unofficial Patch.esp  [Version 1.0.2]33  DLCSpellTomes.esp34  DLCSpellTomes - Unofficial Patch.esp  [Version 1.0.1]35  SM Plugin Refurbish - MehrunesRazor.esp  [Version 1.08]36  mythsandlegends.esp37  StockClothingArmor-forExnems.esp38  ExnemRuneskulls.esp39  FCOM_ExnemRuneskulls.esp  [Version 0.9.9]3A  Cobl Glue.esp  [Version 1.32]3B  Cobl Si.esp  [Version 1.32]3C  OOO 1.32-Cobl.esp  [Version 1.29]3D  Salmo the Baker, Cobl.esp  [Version 3.05]3E  FCOM_Cobl.esp  [Version 0.9.9]3F  Oblivion WarCry EV.esp40  FCOM_WarCry.esp  [Version 0.9.9]41  Oscuro's_Oblivion_Overhaul.esp  [Version 1.34Beta]42  OOO-No_Guild_Ownership.esp  [Version 1.33]43  FCOM_Convergence.esp  [Version 0.9.9]44  FCOM_RealSwords.esp  [Version 0.9.9]45  Mart's Monster Mod - Hunting & Crafting.esp  [Version 3.6Beta]46  FCOM_SpawnRatesReduced.esp  [Version 0.9.9]47  FCOM_SaferRoads.esp  [Version 0.9.9]48  FCOM_NoReaversInGates.esp  [Version 0.9.9]49  FCOM_NoAdventurersInGates.esp  [Version 0.9.9]4A  Mart's Monster Mod - No Blood.esp  [Version 3.6Beta]4B  Mart's Monster Mod - Less Bone Loot.esp  [Version 3.6Beta]4C  Mart's Monster Mod - Vindasel.esp  [Version 3.6Beta]4D  FCOM_DiverseGuardUnity.esp  [Version 0.9.9]4E  StockClothingArmor-forExnems - OOO Patch.esp4F  OOO-Armor.esp50  Fransfemale.esp51  Castle Ravenpride.esp  [Version 1.01]52  The Lost Spires.esp53  bartholm.esp54  Cybiades.esp  [Version 2.1]55  CybiadesDungeon.esp  [Version 2.1]56  Ivellon.esp  [Version 1.8]57  300_Artifacts.esp58  GlenvarCastle.esp59  HoarfrostCastle.esp5A  NakedNord.esp5B  TheForgottenShields.esp5C  VHBloodlines 1.2.esp  [Version 1.4]5D  DLCFrostcrag.esp5E  Harvest [Flora] - DLCFrostcrag.esp  [Version 3.0.0]5F  SM Plugin Refurbish - FrostCrag.esp  [Version 1.03]60  Knights.esp61  Knights - Unofficial Patch.esp  [Version 1.0.6]62  SM Plugin Refurbish - Knights.esp  [Version 1.06]63  TOTF.esp64  Mighty Umbra.esp65  Ungarion1TheWelkyndSword.esp  [Version 1.4]66  Lost Paladins of the Divines.esp67  Origin of the Mages Guild.esp  [Version 5.1]68  MannimarcoRevisited.esp69  MannimarcoRevisitedOOO.esp  [Version 0.1]6A  Mart's Monster Mod - City Defences.esp  [Version 3.6Beta]6B  FCOM_Knights.esp  [Version 0.9.9]6C  FCOM_MightyUmbra.esp  [Version 0.9.9]6D  FCOM_OMG.esp  [Version 0.9.9]6E  KvatchAftermath.esp6F  FCOM_UnofficialFranArmorAddon.esp  [Version 0.9.9]70  300_White Stallion 4.esp71  Versus Dark Brotherhood.esp72  Cyrodiil Border Regions 1.2.esp73  EnchantmentRestore.esp74  EnchantmentRestore_Wells.esp75  SupremeMagicka.esp  [Version 0.79b]76  SM_ShiveringIsles.esp  [Version 0.79]77  SM_EnchantStaff.esp  [Version 0.78]78  SM_DLCSpellTome.esp  [Version 0.70]79  SM_MMMCompatability.esp  [Version 0.79]7A  SM_OOO.esp  [Version 0.75]7B  Francesco's day lenght rescale 1-16.esp7C  Smarter Mercantile Leveling - Multi.esp7D  CM Partners.esp7E  eyja.esp7F  CyrusSkillMult.esp80  Bashed Patch, 0.esp
I moved eyja down as it was glitching, and I played through it just recently, the cyrusskillmult, is a self made mod that just changes how many skill levels it takes to get a bonus, making it 1 instead of 2, so I don't micromanage and just take whatever the result at each level usually acceptable with 3's to 5's on my most used skills that level.