the 3.7 has more hp from 332 to 340 depending on the year, the limited crossfire has 215, the cost of swapping for that small increase may not be worth it, as far as ho you may want to remember that Chrysler had to down grade the horsepower on the srt6 from 350 for the slk to the srt6 . maybe you could gain the hp you want with mods,, looks as the gas mpg is very close.