Hiadee, I almost choke on my hoonkeee when I read that you have found 19" CSP 5P to be cant-make-it.
Well for a start, you should also look at some reviews on tirerack and BTW if I am not wrong, CSC 5P is used on some perf marques like AM and some AMGs (in the USA at least) so how bad can it be? I used 19" CSP 5P prior to my current set of Michelin PSS and contrary to what some say, I actually find CSC 5P slightly better. The downside with 5P is the tyre has a lower wear rate so wears faster, but that's why it is a good perf tyre if you forget about the value-for-money thing for a while. May I also ask how far have you pushed the CSc 5p? you might wanna try taking it up north to Kl or further n pushed it above 200kmh and u can see how steady your car is. dry n wet on hilly winding roads n NSH. What u should not do on CSC 5p is pump the tyre pressure too high. Around 220-225psi will do(cold).
So after all this why do I try PSS now? bcos I got a good deal and CSC 5p was out of stock at that time and dealers sell it close to PSS price(another reason why I don't agree CSC 5P is CMI tyre). PSS has a higher wear rate but I do find the compound of PSS a little harder(but of cos, 300 vs 240 WR?). Both CSC 5p and M PSs are overall good perf tyres.
Oh u are considering GR90 also? It happens that I also used before, for 3 weeks and then I traded off for CSC 5P. My 2 chao ah beng cents is - screw the GR90. First thing u notice is the width problem. 235 isn't really 235. When mount on my 8.5 front rim, 235/30/19 looks like 215/25/19. Farking Bridgestone must be using the wrong ruler to measure when they manufacture the tyre. Ok now the perf or the lack of it. u floor the throttle on NSH, say from 100kmh. u get tyre spin, tail swing, SMLC swing...no confidence at all on same tyre pressure as CSC and Michelin. I tried it bcos they say it is 'quiet n comfortable n grippy'. well grippy it is not.
So my chao ah beng advice. if u are hardcore driver n drives yr machine hard, take CSC 5p or M PSS. If u don't mind faster wearing off, CSC 5P. if you mind, take PSS. Screw GR90.