Blykins If this rear is this hard to get, what happens if you break it and need to replace?? The other thing is Aluminum center sections. They tryed this in the 70's major problem with Buick cars. Every 5-10 years they try again and have gotten better, been 40 years. Have seen GTO center section replace with a little extra hard driving and better tires. Heavy car to start. Vettes are the same issues for the C6. Better to go with a C2 or C3 and buy the 12 bolt upgrade. This is the one they use for drag racing. Good for 900HP. IMO if you are going to do light driving and no abuse, go aluminum. If you are going with 600HP, the only rearend for this would be an Full size Ford expodition. You would need to look at gear ratios. Outside brakes, strong axles, large CV joints, and can haul 10,000.
Can find them in Junk yards and cheaper than other rearends.
The other question is cooling this rearend if you go aluminum, Expension rate again is up to .002" and this is enough to get carrier walk, cap walk, back lash chance. LPW sell rear carrier covers with support bolts to load caps for carrier, well worth the $200.00. Been running one for 14 years, no failure yet. Cooler system will be about $500.00 if you do the work. Good Luck Rick L.