Thanks Cdrc. I am using copper SE cable & 4 AWG solid copper GND wire terminated to 8 feet solid copper bar ( about 50 feet from Main panel) and to water mains. I have bought Cardas in wall AC for two dedicated circuit, 10/2 romex for subwoofer, 10/2 as spare. My outlet are Oyaide R1 with wallplate. Lugs in my meter are copper, not aluminum ( special order from Flexcenter).
I am sort of disappointed that I couldn't get all copper panel anyways , knowing that AL is just 40% conductive to copper.
I wish I could post picture on Audiogon to expain my situation further. Lug for GND ( where 4 AWG attaches in the panel) can accept copper and AL ( it is 6061-T6) and GND strap which connects to GND/NEUTRAL bus bar (BSSUSE Bonding Strap) is also 6061-T6. Ideally, I should be able to replace GND/neutral bus with N174 copper bar.
Again since bonding strap is also 6061-T6 ( Tin plated), copper bar screw to it, should not cause any harm. I am bit skeptical/reluctant after Jea48 comments.