ybk wrote:..... The RS is basically a R with a dry clutch.
Correct for a '92 3XV8 RS but not for the '93 3XV9 & '94 3XVA RS's, as the 9 & A also have the sliding block chain adjusters & fully adjustable suspension front & rear as well as the dry clutch unit. Early SP model rear springs are yellow as opposed to R/RS springs which are red. As YBK says, your best bet is to find out what the frame No. is to pin what model the frame is from, then find out what model suffix is on the base of the engine cylinders & on the cyl. heads, e.g., -10 cyls & -11 heads = '91 3XV2 SP.
There seems to be a lot of "Heinz 57 mongrels" out there these days being flogged as "genuine SP's" when in fact they are a collection of bits from various 3XV models, so do as much research as you can before parting with your money!

My 3XV9 RS was advertised as an SP, but on checking the frame No. before buying, I discovered it was only an RS so was able to barter the price down a bit.

Good luck with it anyway.
P.S. RS = Racing Sport & SP = Sport Production.