Thanks all you guys,for the quick and complete response.

So, I can recapitulate

:
1. Tamiya kit its much better
2. Revell kit are for an 962

3. Bellof 's Spa car are short tail version but tamiya 's kit are long tail version. (An expensive modification are available from Studio27)
4. No "Schiesser" decals available
I am true?
So, some new questions ...
Are Jaegermeister decals for 956 Porsche are accurate for a Bellof long tail car (any possible race)?
Bellof ever raced a 962 Porsche ? (which decals if yes?)
Thanks again.