It is a difficult decision for sure, a standard Aero is a wonderful thing and there are some really good ones on the market at the moment (including my old one!) - in fact I don't recall a time when so many mint S1's were available! So it is a great time to buy one.
For me I fell in love with the GTN as a teenager watching it on Top Gear, the colour, the interior, the engine, all the upgrades, exhausts and exclusivity factor all make it feel rather special and a bit of a unicorn, for me it is the one I have always wanted.. again it is very unusual that two GTN's are for sale at the moment, Shooter's (for sale with O'Kane Lavers) and Richard Thorne have one, so there is lots of choice which is a good position to be in - rather than waiting years and years for a car to become available!
I posted up pics of the spare wheels by the way, if its of any use. They are slightly different to the standard ones (think they are pre-production ones), just deciding if I go for them or not as believe they are abroad.
Feel free to PM me if you have any further queries, I live almost next door to Allon White and they have the cheapest S1 for sale at the moment, Autologix have my old S1 Aero for sale, Krazy Horse have a few and Berrybrook I believe. Oddly they aren't all advertised in the same places, so worth looking at them all before making detailed enquiries etc and see what your taste is, they are very specific to peoples colour/interior choices.