As far as know, If you install ONLY the expansion pack in question (the one with the styles AND the custom drum kits) everything will work fine.
The problems start when you want to mix 2 or more Expansion Packs in one installation file.
Then MAYBE there are LSB conflicts.
In other words every expansion pack has an LSB number and MAYBE two (ore more) packs in a mixed packs installation. can have the same LSB number.
Try first of all to install the expansion pack with the styles and the custom drum kits alone and see if everything works. Then is you want to mix expansion packs you have to experiment a little bit.