wot car does the n75j come fitted on as standard

Audi TT 225, I think.

I was told that they were used on older audi's but i might be wrong

Nope its the quattros of the 80's and 90's

i beleive its the audi s2 from 80's-90's

Why do you ask? I have just fitted one to mine lastweek and it seems the remap which I have recently had runs alot smoother and is holding more boost -still need to get on a RR to prove this

the audi s2 the VAG part number is 034906283J

ETKA parts system lists it as fitting the following

1988-1991 Audi 200/Avant quattro

1989-1995 Audi Coupe quattro

1980-1991 Audi quattro/sport