Trip to Croatia sounds very tempting . I want to go there, but for some Alfa event. I have seen galleries by Paso (I don know if he is the photographer ) at Grobnik. Many good alfas, especially his and alfamaniac's GTV . Sorry for lyrical digression . If you ask me do exhaust before ECU tuning. From turbo backward at 63mm(2.5") or 70mm(2.75"). In practice 63mm will probably be enough. If you lengthen your summer journey to Bulgaria, I can make you a offer for custom exhaust system from stainless steel , hand crafter by one guy in my hometown which has a workshop for such stuff . You will be very satisfied by the price and quality of the work . I'm also fan of Ultraleggeras , but the price just like wheels is also very "good" (here in Bulgaria 260E/piece for 17", 7.5J, PCD 5x100). The right sequence for upgrading of car is first brakes and handling and then power . You upgraded brakes and have suspension for installing (from what I have read FK Silverline X are good coilovers so you probably won't be disappointment) , so probably diff (Quaife is cheaper now than Q2 ) and front strut brace will be more logical steps. And you probably know that original diffs on our cars (and some other models - GTV 3.0,3.2; 147/156 GTA ... ) tend to break and broke the transmission with it and in that case follow very serious and expensive repair. So Quaife or Q2 diffs are not only for improving traction at the front wheels .