Yeah, I noticed a difference... w/ a '99 up stang I'd definitely recommend 3.90's or 4.10's. The PI motors have much more top end compared to the 96-98 NPI stangs that have more low/mid range grunt.
Since it's already got a good exhaust I'm planning on running the ipod cable, adding a subwoofer and amp, and swapping out the stock shifter to a short shifter.Nice, what you got planned for it?
I would get the car a full tune up and new fluids on everything
that's one of the great things about Silver it seems to last a long time on these cars!
If you think it handles well now, wait till subframes, new shocks/struts, springs and CC plates.