The Mopar Performance Stage 3R Turbo Upgrade Kit ($4199) turns the already fast SRT-4 into a racing machine. The 3R adds some manual tools that takes the car to another level. There is a control to spray the intercooler, change boost levels and a switch to change to high octane mode. On 93 octane, the SRT-4 cranks out 310 hp and 325 lb-ft. Hit the switch and stop by the racetrack for some 100 octane those numbers jump to 355 hp and 365 lb-ft. Very cool.