UpgradingGarrett GT2860RS Ball Bearing Turbo A/R 0.64 (Disco Potato)
To
Garrett GTX2860R Gen II Turbo T25 / 5 Bolt 0.64 A/R
When with this over Garrett 307s. Because I want boost to come as early as possible.

 Features:

• Increased Horsepower Range
• Fully Machined Speed Sensor Port
• Improved Surge Resistant Ported Shroud Design
• Lightweight Billet Back Plate
• New Compressor Housing Aesthetics

Specifications:

• Approximate Horsepower Range for Engine Capacity: 200 - 475Hp (1.4 - 2.5L)
• Compressor Wheel Inducer Size (mm): 46
• Compressor Wheel Exducer Size (mm): 60
• Compressor Wheel Trim (mm): 76
• Turbine Wheel Inducer Size (mm): 57
• Turbine Wheel Exducer Size (mm): 47
• Turbine Wheel Trim: 76
• Wastegate: Internal Wastegate

TonyMR2
I am sure you have done your flow calculations (charts online) / plotting flow, as well as chatting with other owners who has a similar build components.

Help me to understand your build decisions, oversized valves aka increase lag yet increase flow for high rpm, upgrade camshafts to help flow, tiny turbo on a tiny a/r would this not restrict hp in the mid to high rpm.

If you haven’t purchased yet, why not go the newer g25-550...

Interested to understand what rpm you expect to see what boost and power band hp (rpm to rpm average hp).

TonyMR2
I am sure you have done your flow calculations (charts online) / plotting flow, as well as chatting with other owners who has a similar build components.

Help me to understand your build decisions, oversized valves aka increase lag yet increase flow for high rpm, upgrade camshafts to help flow, tiny turbo on a tiny a/r would this not restrict hp in the mid to high rpm.

If you haven’t purchased yet, why not go the newer g25-550...

Interested to understand what rpm you expect to see what boost and power band hp (rpm to rpm average hp).

G25-550 is $3300 to buy it's rated up to 550hp this is an overkill for my build.
The Garrett GTX2860R Gen II Turbo 10 to 15% more efficient than the Garrett GT2860RS Ball Bearing Turbo A/R 0.64 (Disco Potato). So 350hp to 475hp increase on spec sheets. I can reuse my exhaust housing with the new turbo and keep all my pluming the same, that save me some coin. 1mm bigger valves is not going to created lag. Going to a T3 flange will. T25 flange will work better lower and mid range revs, Remember I'm will tune this car with 800cc injectors so this turbo choice will work fine. The 265 cams is a balance power and torque. The Links ECU will control the wastegate greep and bring the boost on as fast as it can to 12psi and upwards as revs increase.This boost will happen between 2000 - 2500 rpm. I will not need to run as high boost levels to achieve a balance hp curve. I have had a 348rwkw, 550-600hp Mr2 before it was great for draging etc, not so good for track days as, lag etc. Hope this give some insight.

I can tell you first hand a gtx2867 0.86 housing, 264 cams, 5s bottom end on e85 is a spool monster. Midrange is exceptional.

Yours will be a fun drive by the sounds of it.