Originally Posted by Hunter5179
It all depends what you want. H&R lowers your car more than ACS springs do but as far as ride quality I don't think they compare. I have had H&R springs before and the ride was bouncy. I currently have ACS springs on my car and even though they were more expensive my car rides awesome. It feels so solid I love it. I can whip turns with no body roll and the car just feels solid on bumps. I actually think BMW should put these springs in all their M-sport package equipped cars. That's my take. I would go ACS all the way unless you want to go maybe a half inch lower and save some money but with this car I wouldn't cut corners to save a few bucks when it comes to something like suspension or anything else. This is a heavy car and it needs to have solid quality add on's to get it to feel just right and I'm not saying that H&R's suck because I have used them before but I wouldn't on this car.
I concur with everything Hunter5179 said. I've had all three and the ACS are the best and they are still low on my 550i. H&Rs ride quality on this car is terrible.