I run a 74 LA lancer witha 2.6 astron engine in it, these engines arent to be under estimated, apart from timing chain issues :) they make cheap horse power. my engine has 290 duration cam, heavy valve springs, magna big port roller rocker head, adjustable cam gear, 34 ADM weber, and tuned lenght extractors with a straight through 2.5' exhaust, and 5sp gearbox. it will rev easily to 7000rpm and i havent broken anything yet.
As for saturn 1600 4g32 engines, i have owned several galant in my time and these engines are very reliable cheap and if you get a good one go very well. My stock 4k is gutless compared to these engines, but is still a tidy little unit.
my opinion with your ke20 is to go for the 4G32 they are a good little engine and i have measured up my corolla for one. The only prob i saw was the standard 4sp jap galant box or 5sp jap box are too long for the KE20.
hope this helps
cheers loran