I think you can buy tilting subframes from somewhere. Alternatively, I have a friend that bought a set of recaros from a 5 door and to fit them in his 3dr he simply pulled the foam and material of the seats and put it onto a seat frame/mecahnism from a pair of old tilting seats and then cut around the levers. Worked very well, didn't take long and looks factory, so good in fact that i'm about to do it myself!

Robbo