IHI Turbos 5 Speed vs Auto Part Numbers

I noticed that the 5 speed and Auto 88 TC has two different part numbers for the IHI Turbo. What's the difference between them? Do they install any differently?

Ford Part Numbers:
New Turbo for 87-88 TC E7SZ9G438A (5 Speed)
$1,404.67
New Turbo for 87-88 TC E7SZ9G438B (Auto)
$1,404.67

As far as I know, the turbo itself is the same but I have heard the waste gate actuator(WGA) is different. Not 100% on this but I beleive the auto WGA one will not allow as much boost as the 5 speed WGA....Tommy

The auto did have less boost. but from what i have read the computer and BCS limit the boost in autos. The turbo and waste gate should be the same. Someone chime in if I am wrong.

AFAIK, they are the same.

I've personally swapped WGA's from a 5-Spd to an Auto and visa-versa. Neither's boost changed. It's all in the BCS and ECU 100% for sure.

There are no physical differences in the IHI's either. I have one of each sitting here.

Thanks for the information. I'm in the hunt for a spare IHI. Ultimately I'd like to upgrade to a T3 or hybrid once I understand the upgrade process better, have a firm grasp of the parts required and have confidence in the upgrade plan/reliability of the set up from the fuel tank to the computer, sensors and guages out to the exhaust system. One key thing for me isn't just higher horsepower. It's drivability in traffic, usable power, spool up time, cold A/C, reliability and the ability to run/cope with the high temperatures in southern Nevada. I'd also like to keep my fuel consumption reasonable for road trips.