Probably the GT (cause I have one), but seriously, I picked up a 91 GT with 24K miles last summer for $21K. A comparable GTS 5 speed low miles would cost $50K, $60K, more??
After fluids, TB, WP, Tensioner, tires and some other rehab since it hadn't been driven for 10 years, I added another $4K expense, and what a hoot to drive vs the 89 S4 auto I have.
For the bang for the buck, I'd try and find a nice GT vs a GTS.
