I would say, you have 2 choices :
1. make the bimmer seats fit the crossfire mounting frames, or
2. make the bimmer mounting frames fit the crossfire floor pan mounting holes.

I do not know offhand the dimensions on either, if you already have the BMW seats that should be easy to determine.
You should be able to hack something up to make the electrical work.
( you can get the schematic from the service manual in the below link )