Jarrell;
I have a set of the Recaros that fit the GT, you can find them in the 77-83 BMW 320i series. NOTAVETT has the instructions on his site to mount these Recaros simple and easy using the stock GT seat rails. As Todd mentioned, for the Manta/Ascona, I have found a way to use the stock seat frame to mount aftermarket seats without messing up the floorboards of your Manta/Ascona. Todd is right in that there is not a lot of room to work with in a GT, but, in the Manta/Ascona, you're almost at "the sky's the limit"
Gene