Not at all. Its one of the first things that should be done in the search for performance, after getting the engine in proper tune. The difference between the T3/K26 and a VNT is night and day. 200lb/ft torque below 2000rpm is normal with an otherwise stock engine. Thats at the wheels with a manual transmission, instead of the stock 180lb/ft @ 2800rpm at the engine. An automatic will have even more torque on the low end thanks to the torque converter's multiplication.

Any weekend shadetree mechanic can do it. The flange for the Liberty turbo can be bought for a reasonable price, oil lines are cake to make if you know where to find a hydraulic shop for fittings and the stock exhaust can be used. The hardest part is making a decent air filter system (thats not just an open filter on a tube).

An intercooler will have no effect on torque, just top-end power.