Nice.. There's a few things you NEED to check or look into:
1] Don't wait, do this now! Go ahead and pull the passenger side of the wiper cowl panel and inspect the drainage grommet. These are famous for clogging up, NOT draining and letting water enter through the HVAC via the cabin air filter. Pull it out, cut about an inch off of it [or until it's not touching at the bottom] and replace. Also, if that cabin air filter is any other color besides white or light grey, replace it.
2] Go to a dealership and have the VIN number checked against the TSB database for repairs completed. They have to fix anything that was a TSB item, and the S197's had several of them.
3] If you cant spring for a short throw shifter yet, the polyurethane bushing kit for the stock shifter is a great, cheap alternate
4] Hand held tuner and a tune should be your FIRST MOD PERIOD. SInce the S197 is DBW [drive by wire] Ford left a decent amount of hp/tq [nothing earth shattering, but very noticable. It will get rid of that lazy feel below 2500 rpms] on the table.
5] Skip all other CAI and get a JLT Series 3/110 mm CAI. Period. [our '05 made 318/330 with that CAI, charge motion delete plates, MAC axle back, offroad X-pipe [which I have the X-pipe for sale btw] and a tune.. That's it...]
6] Long tube headers make a HUGE difference. We haven't made it back to the dyno but after we added 1 3/4" MAC longtubes [midlength's really] and a Prochamber with cats it really hauls ass. Even from a dig with 3.55's, helps out in the low end torque department.
Check out S197forum, but be warned.. You think the crowd here is tough, those guys don't play nice with others.