Of all the motors you listed at the beginning of this thread, I think the 3.4 V6 would work best for truck/wheeling duty. But it is likely the more costly swap since you are starting with the 4 cyl. Next in line would be the 7M-GE. Sewing machine smooth inline-6 with great power torque and economy. I wouldn't rule out a 22R-TE swap either. You'll still have the ease of working on the motor with the highway power of the V6 and plenty more if you mod it. The 3.0 is tough as nails and after owning both, quite frankly I think it's a better motor than the 2.4, but probably not worth swapping in.

I guess it all comes down to money. If you're going to the trouble of doing a 7M-GE, you might as well get the GTE with big power capabilities on the cheap.