Worth the effort?

All things considered and with the existing drive train you should be able to melt down the tires off the line. Don't take offense to this but are you positive the rear end is 3.55, are you taken someones word for it or have you check it yourself.

Yeah, but how big are the tires.

A 28'' will tame 3.55's down to 3.17's

All gear ratios are based on a 25'' tire.