I like the look of the 380GT wheels and was wondering how going from 215/60/16 tires to 225/50/17 would affect the ride, acceleration and fuel consumption?
My primary concern is to make the car look a bit nicer without sacrificing comfort or fuel economy.

Lower profile tyres will obviously make a difference to ride, but your tyre choice will play a big role too. Like for like there wouldn't be much difference to the ride comfort. Ditto for acceleration and comfort. Just do it :)

Wider wheels will worsen your fuel eco, slightly, but you'll have more grip = safer. The ride is a bit harsher, but so worth it. Agree with Red Valdez, definitely do it!

How much harsher is the ride exactly?
As I thought 225/50 is not exactly low profile by any means

yeah its not a massive change at all, tbh it wouldn't be too noticeable. My dad as those wheels on his stock gt, i wouldn't say that the ride is harsh at all.

My guess is that comfort difference will be barely noticeable, but the improvement in tyre will make turning more responsive and the car feel a bit nicer to drive.

How much harsher is the ride exactly?
As I thought 225/50 is not exactly low profile by any means
Like I said in my above post, it would depend in part on what tyres are fitted to each rim, so it's hard to say exactly what difference you'll notice. I reckon a 215/60/16 tyre with a stiff sidewall would ride worse than a 225/50/17 tyre with a soft sidewall.

All things being equal, I reckon you'd notice that the ride was firmer if you were looking out for it, but otherwise you'd be happy with it.

I am running the Bridgestone ER30 now and I would go to Michelin PS3 depending on price of course

I have no idea what the ER30s are like but the PS3s have a relatively soft sidewall for a performance tyre. You'll be fine...

Yeah I have them on a Mazda 3 which had the original Bridgstone ER300 tires which were good at the beginning but went bad really fast, and with the Michelins it's softer, smoother and quieter, though this is with 205/55/16