Cardinal Performance
http://www.cardinalperformance.com is the best shop in GA for a motor set. If I were you I'd buy a clip (which they have in stock) since you'll get all the stuff you need for the 5spd conversion (well everything but the clutch line since that's LHD).
Redtop goes into the S14 just like an S13, the wiring is a bit of a pain but it's not a really big deal to work out.
Ebay motor's are junk, stay away from them. There are a lot of shady shops out there now importing stuff trying to make a buck, you really have to be careful who you go through.
hope that helps, give Cardinal a call.
Paul