A lot of people have gone for the R32 rear (myself included) I havea GTI R32 exhaust from Milltek, cost about£500 as you stated,there areother companies out there, I know some places make there own exhausts, but prices are similar to the Milltek prices.
Not heard of the Eurojet ones before though.
As for lowering, it depends on a lot of factors, how wide your wheels are is always a big factor on rubbing issues, also the size of your wheels.
I have had my motor lowered about 30mm and with 19" alloys with no problems,and am not going lower with 18's without too many problems (yet)
How low do you want it?