Yeah I've been a Geoff Crammond fan since Stunt Car Racer. Grand Prix 3 rocked my world but when GP4 and EA's F1 2002 came out, I bought both and ended up playing neither

(though I played the excellent GTR 2002 F12K2 mod for a little while). It felt like I had an amazing game that was split in two and couldn't be put back together again.
I personally feel that Geoff Crammond got left behind a bit with GP4; apart from AI and wet weather (both visually and physically) which I think are unmatched. I also really like the graphics in GP4, though you really need a fairly beefy PC. There are rumours that there might be a Grand Prix 5, but if so, GC prolly won't be working on it (he's working on a Stunt Car Racer remake). Though Sony have just bought exclusive rights to the F1 license for 2003 to 2007 or so.