A while back I moved from a Mk3 16v to an 89 Mk2 16v, both standard cars. And I preferred the drive of the Mk2, much more in touch with the road and what the car was doing. The Mk2 felt faster too and it was lighter, but it was without comforts such as power steering and electric sunroof (my Mk3 didn't have air con). The Mk2 still had central locking and electric windows.
I changed from a Mk3 to a Mk2 because the Mk3 proved to be really dodgy and had lots of problems and although it was still fun, the Mk2 was much more fun to drive and even though it was older and had 30k more miles on the clock, it was in better condition.
I also remembered that it was actually a Mk2 that I originally wanted.
The Mk2 is a classic, the Mk3 isn't really. I would definately have a Mk2 again, I wouldn't bother with a Mk3 unless it was an absolute steal.
As for that Mk2 you've been offered as a swap, get the original tailgate and bonnet on, get some smaller wheels on and swap the bumpers back and then you've got a nice de-chavved car.
Also is it just me or did they forget to change the arches when they swapped from small bumpers to big bumpers?