I realize this is for MR2's, and Matti's site has been a fantastic source of info in the past, but two sites that should be added are Bill Sherwoods and club 4ag. Neither one is centered on the MR2, or even goes indepth on the subject of MR2's, but they contain a great source of info on the 4AGE.
www.billzilla.orgwww.club4ag.com