Oy...shit This has potential to get ugly. Okay we need rules.
IF YOU HAVE RESPECT FOR ONE JUST SAY WHAT YOU WANT ABOUT IT AND LEAVE IT ALONE.
I've seen many topics where one says for instance "Oh yeah ACS rules, fuck hamann"
Then some bmw owners with hamann parts get very angry.
keep it clean.
Anyways, I prefer Hamann because their looks fit my likes a little more. I still like the ACS new IV rims and coupe body kit.
Love hamann rims but for proformance.. I'm not sure. AC Schnitzer has really good exhaust and suspension and their strut bar is pretty awsome. Hamann has great rims imo and I think their exhaust system is made by supersprint or someone so I can't really comment on that. Honestly its all what you like most
Each of them is highly respected and a GREAT company to buy from.
Alpina is just in their own leage. Their products are just all them and thats pretty much self explanitory. GREAT company.