GTX2867 or 3071 IMO. On a 3S, I've had CT26 (165) CT20B, K1, GT3037 (now 3076), GT3582R. Have a GTX3582 on FD too which has been flawless & competed in Time Attack.

The GTX2867 would sit between my K1 (on 2L) & my GT3037 experience (2.1L), which would be the sweet spot for a nicely powered, still responsive & low/midrange punchy turbo.

I had to really push my K1 & motor kinda hard to reach 235rwkw, which although it was very fun, a GTX2867 should be able to do a bit easier without too much sacrifice.

Agree, 3SGTE can be hard to squeeze power from compared to say SR20 or 4G63, but I personally blame unfamiliar tuners, factory intake manifolds (restrictive uneven flow) & widely used, insufficient side mount intercoolers.

I think Alex should contact Trav about the K series. Cheap and easy, bolt on, 230kw is plenty for a MR2.
With that much power, you should be doing 1.09 at Wakefield ,1.50 at SMP and around a 1.39 at Winton as that's what this car is being used for, track work.
Anything else will cost a bomb. Enough for anything between 10-20 trackdays and you would only pick up another 30kw so why bother. Amisavoy has finished his conversion to a aftermarket turbo and it destroyed him. Was off the road for 10 months, cost a fortune and was 2 seconds quicker than his 100kw NA. He is still having problems and may sell up so I really do not believe its worth all the effort of big turbo and all the grief unless it is a drag car or street bruiser but that's just my two bob and I would not like to see you suffer as I and Ian have done over the past few years.    

K series is barely an upgrade. I ran it for years. Wouldn't recommend it now given it'd be second hand unfortunately, unless bargain/excellent nick. At the first club dynoday (which I won many moons ago) I outpowered a gen3 with CT20B, relatively equal terms (boost, cooling, motor) by about 10rwkw. It was fun though.. GTX28 is nowhere near drag or street bruiser territory. I truly dislike CT26's & how they fall over well before 7k, so anything past that is basically a welcome change. I've never in all these years been impressed by a high flow CT26 either.

You have a point re suffering, but every case/experience is different & unfortunately Steve's was bad. Jury's still out on if all that 2GR work will pay off too (should've left it stock unopened IMO). Quite a few powerful MR2's have done well both here & overseas. Keep in mind, Wakefield is not a track that heavily rewards horsepower, especially compared to say Eastern Creek.