It's really personal preference. I've gone thru both.
I'd say go with weld in SFC and Suspension. Really makes it feel like a different car.
Exhaust will really make the car sound mean, but you'll still have a slushy ride. May have to worry about emissions and checking up on the piping headers from time to time as most of the bolt on exhausts loosen up a bit after time with some spirited driving.
dunno about a stall. M6 here, but everyone says that is always a great mod, but may be more than you want this moment.
