Engine swap.
 

I was thinking about taking the a NA MKIV and putting a 2JZGTE in it. I have a few questions though which is what brings me here.

First, would this make sense to do as far as it being cheaper then trying to get a tt supra.

Second, How difficult is it to swap the motors?

First, it makes sense to do if all you want is the horsepower from the tt. What you won't get is the braking and suspension capabilites of the tt, nor will you get the high-horsepower-capable transmission and differential of the tt. In other words, an n/a with a 2jz-gte does not have anywhere near the overall performance characteristics of a tt.

Note you'll also have to change the primary wiring harness and ecu. You'll also need to purchase a resistor pack and an ignitor. Iow, your n/a ecu can't control the tt engine.

Assuming you're talking about a 2jz-gte FROM A SUPRA (i.e. NOT from an Aristo), the swap isn't that difficult, relatively speaking, for a mechanic that is experienced with the mkiv, and that also has the TSRM on hand. In theory, it could all be done in a day, assuming everything is on-hand and ready-to-go, and you've got someone on hand with a TSRM that has done the work before. Without the proper tools (including a very good torque wrench), the job is impossible to do properly. Without the TSRM (or a mechanic that has literally memorized the TSRM, including the exact torque spec for every bolt), the job is impossible to do properly. (Trust me, you don't want to be blasting down the road at 150mph+ in any car where it hasn't been put together according to factory specs). If a mechanic that is not experienced with the mkiv is doing the swap, with the TSRM, count on at least two days to do the swap (more than likely at least a week). Oh, and if you're starting with a 2jz-gte NOT from a Supra, then add another half day at least (really!), to swap oil pans, etc.

P.S. Did I remember to mention that you should not attempt this swap without the TSRM? :) Not sure if I did, but that's REALLY important.