<cracks knuckles>
LSD - not a problem. Most of the Supra rear ends you'll run into are LSD from the get-go. Factory, you have several choices, including Cressida gears, Soarer gears, and older Celica gears (If you're N/A, 7MGE)
Longer gears are nice. I wouldn't mind them, but consider what you're actually doing. You're building a car that will be in daily ranges (50-100 mph) not a OneLap car (160-180). The longer gears will be real nice on the highway, but think if this is really where the car is spending most of it's time.
The shorter gears will also be nice, but the turbo will get hot with spirited driving (I say this mostly from personal experience).
My stock 87 topped out at it's ranged 150 mph. It had the .. lemme think... 1:4.08 (? Clayton ?) in it.
Off the line wasn't too bad (welcome to real torque) but moving all of that mass wasn't helpful on the overall strain of the motor, the gas use, and driveability.