www.club4ag.com
www.ae92gts.com
Alot people either do a 4agze swap from the early MR2, or take a 4age 20v and throw it in there. they make decent power and are alot of fun to play around with.
www.jarcoinc.com has great prices on engines and stuff
oh and i tihnk most people who get an SR5 generaly the first thing they do is do a rear disc conversion, Its something you might want to look into.-
if ya look around those 2 sites you can find just about everything you want... theres also a site called paradiseracing.com or something like that that sells aftermarket pistons and rings etc... for the 4age/z motors