^^ i'll probably get the Sparco EVO 2's (im a big guy 6' 250lbs) the mounts are car specific, unless you want to modify a set, i know momo makes mounts/rails for volvo, im sure sparco must too since thats what they ran in the BTCC.

you want dimensions of seats they have 'em here: http://www.sportscar-parts.com/sparco_seats.html