Spring/shock vs coilover for comfort

[Varinn]

Been thinking about this the last few days, my car just hit 80,000KM and I'm expecting it to need new shocks soon. I'm trying to decide on a comfortable setup for an '07 Z4MC, preferably on the lower end of the cost scale. It is a daily driver car, I do not want to have a large drop from stock as it is my DD. When comparing between the H&R coilovers, Bilstein PS10, and Eibach/Bilstein spring/shock set; which is likely to produce the best improvement over stock in terms of comfort and driveability. I know that good coilovers can greatly improve the ride but the budget does not really allow it. I have also read that the H&R springs are a no-go for these cars, but the eibach/bilstein combo seems to get mostly positive reviews for someone looking at a moderate street improvement.

My wheels are going to be 245/40-18 on 18x8.5et35 up front and 275/35-18 on 18x10et25 in the rear. I am hoping to keep the drop minimal enough that no camber changes are required from stock to avoid rubbing.

[Steeler]

Research the Koni yellows to go with the Eibach's. Excellent combo.

[pokeybritches]

It's a matter of spring rates and dampers. The stock M suspension has progressive springs that are initially too soft and then are too firm. The pros of this spring setup are that it absorbs small bumps fairly well, and large bumps don't cause coil binding. The cons are that the car feels sloppy and turn in is slow... it will dive under braking, squat during acceleration, and hesitate to change direction. Once there has been some spring travel, the car is very firm and not as predictable as it would be with linear springs. The car feels crashy and harsh over large bumps and potholes. The stock dampers are very firm too, and that doesn't help matters.

If you're willing to give up some comfort over small bumps in favor of compliance with large bumps, and increase predictability, go with some soft linear springs and adjustable dampers. My G-Power car has soft linear springs so it is very easy to drive while eliminating slop, and it's lowered so that it improves handling further. I gave up a bit of suspension travel, and I occasionally find myself scraping the tires over large bumps at higher speeds with a lot of weight in the car. The car is better over very rough roads.

So to answer your question, you can improve the ride, but it will require a compromise in some area.

[pokeybritches]

Also, you can do the dampers now and then convert to a full coilover setup later when your budget allows. Look up TC Kline's website.

http://www.tcklineracing.com