From what I understand the IRS has very nice ride quality. It always irritates me when I feel the solid axle skip and wag a bit over highway bridges and divided pavement sections, I wonder how much better the IRS feels in everyday driving.
If its anything like my car...night and day. But I'm sure my longer wheel base and additional weight plays a role in how my car rides as well. But all of the guys I know that have gone from a GT, to a Cobra all agree the ride is much improved.

I'm sure there are a few reasons for staying N/A but our motors love boost and so will you.