OP: if you're looking for a track car then you definitely need a GT3/RS. No car has any feel close to a analogue GT breed by Porsche.
Even though M3 is a great multi purpose car, I don't feel like it can compete with a GT3 on any performance aspect.
Aston Martin is a show car that looks, and sounds phenomenal.
Merc SLS is another head turner but as a Mercedes the handling is not a priority as usual...
2013 E92 ///M3 Space Grey w/ Fox Red
M Performance Exhaust, KW Sleeve Over Kit, and cosmetic upgrades