Suggestions on spring rates
 

I'm looking to upgrade form my RSR iSport coilovers to a set of MCS coilovers. Car is driven on the street as well as track and autoX. Car also has an LS3 swap but it shouldn't end up weighing too much more than stock, around 80 lbs. most of which is in the trans. Because of this front to rear weight distribution should actually be better than stock. The RSR's are 6K front and 7K rear. I'm wanting less of a compromise for track driving while still being reasonably compliant on the street. I do like having the rear slightly stiffer than the front although I know this can be adjusted with sway bars I'm thinking of keeping a rear bias on my next set of springs something like 8K front 9K rear or 9K front and 10K rear. Thoughts and or suggestions?

I have MCS 1WNR single adjustable coilovers with 8K Swift springs all around, but I doubt they’d be ideal for your needs - what model MCS coilover you have and what tire do you intend to run both on the street and the track? Also, have you contacted Vorshlag Motorsports? They’re an authorized MCS dealer, they helped develop the MCS application for our cars, and they make a killer (if ridiculously expensive) LS conversion for the platform - the point is that they have a lot of experience directly applicable to your configuration.

MCS support should be able to give you a starting point as well. Give them a call or email. They recommended 10k/11k for my car for the track, and even autox (stock size bars). I run 5k/9k but with a 22mm Perrin up front on stiff and Mann eng rear bar on stiff. This is an autox setup but I have tracked the same setup many times with great results. However, I would not run that if it was a full time track car.

Pretty sure Vorshlag also has an LS swapped FRS so definitely reach out to them, as mentioned already.