When I ordered my new GT I ordered standard 16" Alloys and then when I got it I put a set of ultra light OZ Racing 17s on along with Pirelli p zero neros (hoping to reduce unsprung weight at the same time!). I have to say this was quite possibly the worst decision i could have made not only did it cost me nearly £2500 on wheels and tyres but it ruined the balance and poise of the car.
I don't really care how hard the GT rides in fact I like to feel every bump, but with the lower profile rubber required to put on 17s or 18s there was simply too little compliance left in the suspension. Every little bump would throw it off course and although the initially turn in seemed great it would always end up pushing the nose wide as it hit even a tiny ripple in the road. It was so crashy and at times felt like it was running out of suspension travel.
Putting the 16s back on transformed the car, the steering feel and the way it simply flows from corner to corner now is nigh on perfect. I can't believe how much faster I can now corner!
When you do a bit of digging you realise that Alfa setup the GT to ride on 16s with 205/55s and as such the springs bushes and dampers were all selected to match. The wheel an tyre are just as important to tuning your suspension as any of those components. So putting a different size wheel and tyre on will effect the handling and steering.
In my opinion the GT looks great on bigger wheels but the trade off in handling is simply not worth it.
I use my 17s on track days where they prove better as most tracks are quite smooth! But If I am banging up the kerbs I still think the 16s give me an edge! But I rarely use the GT on a track!
But on a typical road the GT is much better on 16s... I am going to try it on a set of 16" Michelin Cups and see how that effects things.
When I test drove the GT its was on 16s and it handling was fluid, tight and smooth possibly the best handling car i have driven for many years. I also tested a Berea V6 which by contrast just did not have the same level of driver involvement, grip or fluidness in its handling. So despite not being bale to get the V6 GT i ordered the next best thing the JTS :-)
I always put drive involvement and handling top of my list when i buy a car so i don't really care about not having 17s on it, doesn't bother me in the least!
Reminds me of when the Alfasud lost its 13"
wheels in favour of 14" and stiffer suspension the handling definitely suffered!
Anyway GT + 16s is the way to go if you want to get the most out of it! It makes a indescribable difference in my opinion - I honestly didn't think it would change the car so much!