Most of your engine questions answered here!
Look through the FAQ first, it explains alot. That post is from the FAQ and will fill you in on most of the common engine swaps. Most engine swaps don't require any chassis modification more complicated than taking a BFH and making a dent in a frame rail and buying a mount kit.
Also, Honda engine codes are usually found on a small flat area on the front of the block on the tranny side of the engine(it will be on the left side of the exhaust manifold by where the trannsmission mounts on most engines...don't know for sure on the K-series, or some of the V6 engines)
VTEC-Honda's Variable Timing, much like what every other import maker has..each one has a different name, to tired to name them. VTEC in short: low rpms=a less aggressive cam lobe for better fuel economy, and probably other reasons, then once you hit a certain rpm, it kicks the rockers over to a more aggressive cam lobe giving you better top end.
VTECH-They make phones...not motors, or anything to do with motors.
Do some more reading and become friendly with the search function here and your favorite search engine. Lots and lots of good reading on the net, just gotta find it(its not hard)