Hi all, this is the first posting I have done on this site so be gentle

I am looking for advice on mods for my 1991 MK1 cab, these are
Wheels..... There seems to be numerous people stating all sorts in regards to what wheel sizes etc that I can get on my cab with no mods - please could anyone clarify? (Adam B big fan of your work on the orange cab BTW) any specific wheel examples would be cool too!!!
Lay flat rear windows - do these things actually exsist, if so can anyone point me in the right direction?
What is the best exhaust (manifold down pipe backwards) - would like to have a performance upgarde without any silly 10" tail pipes
I have had my car for 2 years now and have minted it to standard spec (genuine 62,000 miler) but now have a little money to burn and would like it to look phat for future shows etc, the only thing I have done (apart from renewing everything, roof, paint, interior etc) is I have dropped it by 40 mm, any mod advice is more than welcome here!!!!!
Thanks all!!!