20k is fairly low for this kind of vehicle. It'd be fine for a taxi or what not, or maybe LOD1 or soemthing. For reference the Formula Masters cars in Race07 are ~28k and the F1 games from Codies are just above 30k.
Normal maps aren't something I'd be using - they're for per-pixel changes in normals. A lot of the bodywork on a F1 car is gradual curves over a set, continuous shape, something you should b using mesh for (no normal maps on the body ideally).
For the shape of it, it seems a bit generic for a 2009+ F1 car - no offense. All the top teams had some sort of concept that you could see visually; Brawn had the sweel long nose and pushed sidepod shape, Red Bull had the platypus nose and tucked in the top of the bulkhead (and even tried to continue it this year), Torro Rosso had the 'double floor' and McLaren tried some interesting things the last few years:
^Torro Rosso Double Floor (underneath the Red Bull logo there's a wide, flat gap down to the floor)
For tyres, look up pictures of used F1 tyres, with graining and wear. Even slicks look good and less 'clinicly unrealistic' (common problem with rendering tyres) when they've been 'used'
Some references for green-coloured cars if you want: