I plan to buy dawnguard later today, I was just wondering will all of my Mods (Texture pack) etc etc be rendered useless after i have finished installing it?

I just want a heads up,

Thanks

New textures used in Dawnguard will be standard quality while re-used textures and vanilla content will remain higher quality.

It is possible for mods to interfere with Dawnguard but that depends from mod to mod.

It's all about load order, if you load Dawnguard first, other mods will overwrite if needed and vice versa.

Are there any HD packs out for DG as of right now?

don't think so