The SRT is considerably faster, unless your N/A has a V8 conversion in it. The SRT is good for just over 100 more HP than your car is before your mods. And a CAI and Tune isn't going to get you ANYTHING near 100HP.

And $9995 for that car is a steal - $12K is probably about right, seems like I've seen several around the 65,000 mile mark sell for 12-13K this summer.

Of course, that is, unless there are problems with accident history, etc.