3.1L is a GM motor. Good news is, parts availability out the wazooo! and i believe there is an article on the main page about power tricks for the GM 60* motor. On the bad side, this motor would be considered weaker than the 3.2 and 3.5L Isuzu engines that came in the later Rodeos. Also, since you got the GM motor, you get the rear GM 10-bolt... not quite as favorable as the D44 rear. But all said, its not a bad or stay away from motor i don't think.

towing? how much you talking about towing? you should be good for 4000lbs and under no problem.

-Rob