I'd ask Kev Rooney (Kapri on here) for advice - I'm not being sarcastic when I say that he knows more than DVLA...
There's no way that you can put a second engine in a Mini without modifying the shell. Accept that, get the IVA manual and put aside £490 for the test.
I think procrastinator raises a decent point - which engine number do you use? If that can't be got around and you stick with a single engine, why not put the 20v in the back? There was a rather wicked little Polo a few years back with that set up.
There's no way that you can put a second engine in a Mini without modifying the shell. Accept that, get the IVA manual and put aside £490 for the test.
I think procrastinator raises a decent point - which engine number do you use? If that can't be got around and you stick with a single engine, why not put the 20v in the back? There was a rather wicked little Polo a few years back with that set up.