easy swap is the B18c GSR engine
straight swap, easy, and reliable
I think for LS-vtec it depends on your honda know how
My brother in law and I put together a LS-vtec
it's been 7 years and still runs great and strong
what most people seem to do wrong is they just slap a vtec head on and they think they're ready to go, but a Ls block CAN NOT supply enough oil pressure for the Vtec head, this is important when vtec engage, I see a lot of people make this mistake, and than complain that a LS-vtec is unreliable.
The Ls block does not have a Vtec oil passage (you need a hole to produce the oil pressure to lock the vtec lobes rocker arm) so you will need to tap the hole on the head or weld it shut. When threading it shut use a 1/8ntp fitting. Its best to have a machine shop thread it for the 1/8th fitting and then just screw it in. Next you have to make an external line from the oil pressure sender to the head. Use a 4an to 3/8th ntp plug on the head to a steal braided line to tee'd of to the oil pressure sender hole. You will need a 1/8th tee fitting, a 1/8th to 3/4th's fitting for the line to the tee, a 1/8th to 1/8th adapter to plug the block, and plug the oil pressure sender in the back of the tee. So it will look like this (the T will be used as the tee fitting) 18th to 1/8th adapter T oil pressure sender sensor oil line to head. A suggestion is to have the tee fitting so it is not directly on the block (especially if you are installing an oil pressure gauge) as it can literally crack the threads and you will shoot oil everywhere. So try to run ss lines to someplace that can support the weight.
a properly done LS-vtec is just as reliable as a GSR
if this sounds too complicated for you than just go with a GSR
and avoid the headaches, because that's what you'll get if you do not know what you're doing
