[87DakBuilder]

The 3.9's came in Gen II/III, so you won't have any problems with the engine bay compartment. Also there are way more mod's for the 3.9 as opposed to the 3.7's at this time. Keep in mind what Mike/Sho said is true. The 3.9 has the advantage of a longer production run, therefore there are more known mods available for that platform as opposed the the 3.7. The 3.7 and 4.7 suffer from the same problems which are lack of aftermarket support in the way of performance parts...... Stock for stock the 3.7 is a better starting point, as it makes more hp/tq, but that is about it, the 3.9 has the avantage of intakes mods, along with underdrive pulley's, cams, pistons, and TB's that can be swapped, not to mention exhaust and pcm upgrades, depending on which version 3.9 you have. I'm very biased as I've built two 3.9's, and I'm planning on doing a turbo version of one in the near future, but in the end the choice is yours bro. Be different like all of us Dodge fanatics.