Let me put some words here, may be will help.
Is there difference in AAC and ABC-yes in performance, AAC is better (from my knowlodge and expirience), but there is more invlved then just simply better performance. Manufacturing is more expencive on AAC, handeling is real trick (very simple glow plug's filamnet fel off will kill sleeve on AAC). In the mean time it way easier to match piston material to AAC sleeve then to ABC. So it is complex of issues and problems to deal with.
We did made one piece sleeve with ports and cooling fins on PS12, then we switch to BRB and lastly we used Bi-Metal sleeves. The best results in terms of performance and durability was Bi-Metals, it was easier to control expention of sleeve, but to fuse 2 metals was a chalenge. Fusing seem has to have in the same time expantion rate of both metals we put together, should be strong ehough to do not separate while engine is working and chrome plating should stay on the seem. That was big job and we did it.
Well, due to some thing was changed, I have quit hobby and now working in totaly different industry. I am able to use a lot of development from RC in my current work very succesfully.
Good luck guys.
DISCLAIMER: Since 90% of my posts may be BS, and since my posts may be either insanely idiotic, incoherent, and/or not even close to a rational thought, please accord my posts no more than 10% of credibility.