seems like you have your mind already made up but I must say I can't agree with your decision. a sticky 215 can't make up for contact patch plus the extra sidewall is not going to help especially since you don't have camber plates. there's a point on diminishing returns and with you going to 215's you have certainly passed it imo. you would be surprised how adequately sticky the PSS' are. personally I tracked my car on the RFT's when I first started and even the RFT's had very decent grip plus plenty of my track buddies tracked their cars on PSS for a year or two. I say go out and try out the PSS on the apex wheels first
"I would quote everything pixelblue said, but you've already read it. Take it from someone who's put the 1 through its paces"