Scope mounts for the M1A have come a long way over the past few years. Sadlak Industries have pretty much solved most of the problems with the Art II mount. One problem is the Springfield receivers are not mil spec. Sadlak provides a kit that will allow you to determine if this is a problem and will, I believe, fit a mount to your receiver. IMO the best scope mount out there is their titanium mount. It will set you back about $400 and a really good set of rings will go for another $150.
I know this will open a can of worms but, personally I believe the Poly Tech receivers imported in the early 1990's are some of the finest available. They were forged and the Springfields are cast. Of course there are good cast receivers and there are bad forged ones. LRB makes a good one put they are very expensive. The Polys have received a bunch of bad press that is largely undeserved. The Poly receiver and chrome lined barrel are excellent. I have never seen a Poly dent cases and I usually only discard cases after 4 - 5 loadings.
Most M1A's are ammunition sensitive. The Federal Gold Metal Match is the standard but is also expensive. Yes, you do need a good cheek rest and there are several out there. I Like the one from DWP. I also have one sold by Blackhawk but it was made in Vietnam! Nuff Said?