[ reposting in a more appropriate / focused thread! ]
Yesterday I did a first quick twisty road run since installing
Redwood Öhlins DFV Performance Sport coilovers with the optional
Redwood billet aluminum pillowball top hats + MPP FLCA bearings + MPP compression rod inserts + getting the car aligned.
Other car setup: I had already replaced the Uberturbines+PZ4 with 245/45R18 Bridgestone Potenza Sport on 18x8.5" Titan7 T-S5 forged wheels. Ride height at all 4 corners is matched to this car's stock height at the rear. (Going low is not for me or my wife or the places we drive.)
Dampers are set at 11 clicks from full stiff front+rear, which is about 2/3rds stiff (full adjustment range is 34 clicks if I recall correctly),
I haven't tried other damper settings yet. (The DFV have one adjustment knob for compression + rebound.)
As background, around here most low-traffic twisty roads have lots of very tight turns and nasty ill-maintained pavement. They can be a challenge for suspension control beyond just cornering forces. Racecar stiff and low is not right for them. Nor is too soft though. The stock suspension was a mess if you got going real fast (still within limits of stock M3P grip), the car would get real floaty and bouncy and the weight would keep shifting all over the place out of sync with the actual road and driver inputs.
(There are smooth, well-paved twisty roads too of course, but most of them are either much higher traffic, or a bit of a detour from my regular driving, or they have homes / businesses / etc and are completely inappropriate for fast driving. I'll test the new suspension on smoother, higher speed twisties when I have a chance though.)
The best way I can sum up the new setup is...drama-free. It's firm and sporty yet not harsh, it smooths out rough stuff much better than stock suspension. It feels always stable and in control, like nothing can upset the car now (short of impacts where you stop and look for damage after). The wheels follow the road, the weight stays on the wheels, the reactions stay prompt, and everything just flows. The car moves with the road as needed but not more than needed. You feel the road but it's not beating you up about it. Even when I went fast over a big dip where the M3P ran out of rear suspension travel, it somehow oozed almost gently into the bump stops, and then rebounded promptly + accurately without any further effects. Felt in control and
much smoother than stock. With the stock suspension going fast over a dip like that the car would slam really hard into the bump stops, and then struggle to regain composure afterwards.
Ride quality with the pillowballs and dampers at about 2/3rds stiff is
comparable (not identical!) to stock on better roads, and better than stock on bad roads. The worse the pavement and the faster you drive over it, the bigger the ride quality improvement. The ride is a little different though,
for sure you can tell the it's firmer, especially at low speeds over mildly messy neighborhood roads, but it's more controlled without the stock bounciness, so overall the ride feels at least as good to me, and often better.
About the only time the stock suspension rode better was when going slow over rough bumps or roads. At a certain range of slow speeds this suspension just moves the whole car up and down to follow, whereas the stock suspension would smooth things out a bit more with its bounciness/springiness. Drive faster/harder and this suspension smooths out more without losing control.
[ My opinion of the ride does reflect my preference for firm control over any bounce or float. If you want your car to glide over the road and really filter it out like a good air suspension then the "Performance Sport" coilover kit + spherical bearing top hats aren't what you want.
Based on this setup I would guess Redwood's GT kit + stock top hats can ride real smooth, and still be a big handling upgrade thanks to vastly better damping than stock. (Heck probably a bottle of quality olive oil would dampen better than stock...) I've read the GT spring rates are significantly softer than Performance Sport, and the dampers are tuned to match of course. This Performance Sport kit is right on the money for how I want for my M3P to drive, but I'm pretty curious now how the GT kit feels and handles. ]
Everything above is just trying to compare the suspension mods vs stock suspension. If you include the upgraded wheel+tire setup my car easily rides better than 100% stock, but that's not a fair comparison. However I did make a conscious decision to pair taller sidewalls (245/45R18) with the firm "performance sport" coilover kit. I think the result is much more to my liking than rubberband tires + softer suspension. I also picked tires that were reported to have very sturdy sidewalls and sharp steering response, and that surely helped. These 300TW Potenza Sport feel more sturdy and responsive than anything else I've used in the "max performance" category, they really feel great in 245/45R18, and also grip way better than the OE Pirelli PZ4.
If there's any notable street handling limitation still remaining, I'd say it's the Model 3's lack of suspension travel, especially in the rear, and low ground clearance. That's not the fault of these coilovers, in fact it's less of an issue now with stiffer springs + better damping, but fundamentally the Model 3's limited travel and clearance is still there. Redwood does say this kit is good for a small lift though if you want...
I'll try turning down the damper stiffness soon and see how that affects ride + handling. And hopefully in the next week or two I'll end up on some longer twisty road runs. This was just a few miles for quick fun and to make sure everything feels good before my wife needs the car for a longer outing (involving a lot more twisty road miles).
Maybe Redwood could help build an Öhlins TTX based setup if you're building a straight up track/race car. 
