For F1 I’d maybe try and span a greater era. Keep the F2002 and the MP4/4, but maybe replace the RB7 with something like the Lotus 49.
The three Le Mans picks are great, but it’d be good to fit a 1920′s ‘Blower Bentley’ somehow as well.
For rallying I’d definitely pick the Stratos. Also the 555 Subaru Impreza is one of the most iconic liveries ever so it’d be a crime to miss that out.
Touring Car wise the blue and yellow BTCC Renault Laguna would be great, but I’d also suggest the Alfa Romeo 155 – it raced in the BTCC and DTM with a similar livery and both to great success, so it kinda covers two series with one car/colour scheme.
My picks would be:
1) Ferrari F2002
2) McLaren MP4/4
3) Lotus 49 (Or another iconic pre-1970 F1 car)
4) Audi R8
5) Porsche 956
6) Ford GT40
7) Bentley 4 and a half litre
8) Lancia Stratos
9) Subaru Impreza
10) Alfa Romeo 155 BTCC/DTM
I realise that’s 4 Le Mans cars and only 2 rally cars, but the Le Mans 24 hours has a much longer history than the World Rally Championship (which only really came into being in the 70′s).
I’d also suggest somehow fitting a pre-war Grand Prix car in – A Bugatti Type 35, Auto Union or an Alfa Romeo P3. Possibly replace one of the Le Mans cars for one (I’d be inclined to lose the Porsche, but it’s a tough choice!)