I ran the GTX3071. Its too big for circuit work. Never on boost when it counts. Keep it as close to standard set up as possible or you will spend a lot of money and time and stress for little gain.
Just replace the stock turbo with a 28/60 something, internal gate, sleeve bearing. Cheap ,simple, bolt on,  very similar power with better torque.
Do not buy a ball bearing turbo. If it get hot it will fail the bearing then dump the broken bits into your engine. Based on my last experience with 3SGTE turbo upgrades. You could always fit a supercharger. That would be pretty cool!
If you want better times, spend the same amount of money on SPAX coilovers which would be custom rates for your car. Then drive training.
 

I agree with Jay on this one.
 
3071 was awesome on Pats Red SW20 and had torque everywhere (yes that was 2.2l and running a small rear housing), but even on 2litres with the baby rear housing in my opinion would be perfect not oversized. He was running out of puff up top.
 
These new GTX29's sound interesting and could be the ideal setup. Every GT28 turbo on a MR2 over the years i have seen has been rubbish. For some reason they just never perform right. 

I'm thinking of 3071 for mine though not 100% decided yet

Have settled on a Garrett GTX2860R with "stealth" adapter from ATS racing. Between the smaller 28 turbine housing and light weight billett smaller sized compressor wheel, it should spool up really quick, and pretty much just a bolt on to stock manifold. Supposedly the peak power "sweet spot" for this turbo is around 300hp (220 rwkw) though it's limit is still a bit higher. The guys are also relocating the W2A core over to the LHS, and putting in a decent oil cooler on the RHS. Mock up is below. Probably overall less volume of piping to charge, so the response once all done should be awesome. Now it's just the wait...
 

It's gonna be super responsive and awesome in the low to mid range!

Do yourself a favour and fit a ST162 intake manifold before you cook the engine lol.

I now use one of them and it doesn't flow evenly either. It's better than the stock 3sgte manifold though it isn't perfect

ANYTHING is better than the stupid stock MR2 turbo manifold! :)
 

Agreed. It is truly s h i t e!

Here's the st162 manifold