SBT wants $1300 for a rebuilt 951 and I don't think that is shipping included. The DI is a few hundred more which I don't quite understand.
I was just being general with the $1,000 price. FullBore is $950 for a 951 rebuild, not including shipping.
The R&D head should get you around 150 psi of compression (130 is stock), so yes you will have to run a minimum of 91 octane.