yes using cheats will block the percentage, hence not being able to achieve 100%. but that's all as far as i know, so if you dont care about that you'll be fine.

really? i thought you couldnt get 100% or certain rewards if you had cheats enabled.

quote ChiroVette

because just playing Co-Op with someone who has "cheats enabled" (the message on their save) will cause the clean save to become a cheat save. Apparently in Co-Op, cheats enabled is a viral.

you mean only if you save the game right? i have a clean save and play with people who have cheats activated all the time and it doesnt change my file at all. i never save if someone else is using cheats though.

i also keep my save backed up on the flash drive that came with the collectors edition, in case it does get saved with cheats i can just replace it.