My bad, Ben's sold his already.
 
I can find you a clip+ harness + gearbox from Japan if you're keen. it wouldn't be particularly soon though as it'd have to come in our next container.

If you dont mind working on the car, then buy a gen 3 halfcut (through Dylan) and honestly, the swap isn't that hard. There is heaps of info out there on how to do it and if you get stuck, I'm sure either myself or others can give advice.
You get to learn sooooo much more about the car in the process. And its fun lol.

Don't buy a gt4 engine as there are differences. Not heaps but enough to be troublesome. Honestly if you want to get the experience of stuffing around with cars buy a cheap turbo an rebuild it or enjoy the NA. I have gone through this after a failed 3sge and lots of heart ache.

It would be worth you doing some googling to familiaris yourself with what is really required for a conversion. If you already had a turbo MR2 and were just using the long engine from a gt4 I would say go for it but becuase you dont have different cam covers, or dump pipes, intercooler, intake pipe work etc your will have to buy these on top which makes things more expensive. As already said you will need hubs to run the E153 gearbox and shifter cables, change fuel pump then sort out your wiring for a turbo ECU, intercooler will be needed also. I cant think of all the bits and pieces but as said by others a half cut gets you most things, maybe not shifter cables and fuel pump. An even after you buy the half cut your installing an engine of unknown condition and could need work as soon as you run it. Sorry a bit off GT4 topic.

Haha thats bro any advice is good

Out of curiosty what is the budget you've set aside to do this conversion? If you are buying it all in pieces (not half cut) and paying someone to put it all together you could be spending $5-8K (Gen2) $6-10K (Gen3) in total at a guess.
 
As mentioned already if you buy a 3sgte from a GT4 it will be even more stuffing around buying the necessary parts to setup the engine for an MR2.

I ended up doing a NA to turbo conversion a few years ago. If you can get the motor out from the same year as your car, you can just find the passenger side body loom (which goes from the passenger glove box section all the way to the fuse box and all the way to the back lights). This in combination with a turbo ecu and turbo engine loom (and turbo engine) would allow plug and play, no wiring changes necessary.

I used a Gen 3 gearbox that was sourced from Gorilla Industries, it was in excellent condition and the service from them was top notch.

I also found it a great opportunity to use an aftermarket intercooler instead of the original one, but the stock factory units are cheap enough.

I believe the engine conversion with gearbox worked out to about 2.5k-3k with a new clutch, gen 3 lsd, full body wiring loom and engine. The motor I bought even had an aftermarket dump pipe and CT20B turbo.

The learning that was gained from doing the conversion yourself can be very rewarding. 
 
If i'm not mistaken the back hubs were different on the E153 boxes (didn't mate with the cv shafts) but these weren't particularly hard to find. Shifter cables can be sourced with the gearbox.
 
With this method (as a pose to buying a turbo mr2 and selling yours) is that I had a fresh rear main seal, new clutch, new gearbox fluid etc.
 
I just completed a Auto to Manual Conversion in a Toyota Caldina ST215 (gen 4 3sgte) and it took me 7 months to find all the bits I needed for it, the overall project would be cheaper than buying a manual Caldina (by the time i sell mine and pay stamp duty, roadworthy etc) and I enjoy the car more knowing i've done that work myself.
 
The main thing to decide will be what your budget is (always add $500-$1000 to the budget as something always comes up) and what your technical/logistical skills are like to complete it (logistical as you will need to lift the back of the car up enough to clear the motor, and store the gearbox and engine or even transport them from the location that you've bought them from).
 
Technical will not only be removing components but doing it safely, cars are unforgiving and removing parts and not installing them back properly (or tight) can be very dangerous especially when it comes to Flywheel bolts and subframe/suspension bolts.
 
I say go for it :)