its quite similar under the facelift yeah, but there were a few differences. mostly minor things like the plugs on some of the electrics etc. still same fusebox and running gear mostly though. dunno why i asked if it was a B3 or B4 actually, part numbers for the subby are the same anyway!
which begs the question why anyone thought it would be possible to swap over as its obviously completly different. unless they meant the front subframe...
