IMO the SRT-6 is the best bang for the buck on the market. The most typical mods are CAI, SC or crank pulley, and a custom ECU tune. With just these mods, you are in the low 12 to high 11 sec 1/4 mile range. The SRT will do between 156(rev limiter) and 180 MPH depending upon mods, and the rev limiter being removed. These are very reliable cars, but have a couple of common issues. The inter-cooler pump, the relay control module solder points, and the crankshaft position sensor. Even if you had issues with all three of these, you are looking at less than $200 to fix these issues with how-to's from the forum.

Good luck, you will not regret the purchase of one, and I have never read a post where anyone that has purchased one has regretted the decision.