Wonderful, further propagation of another overexaggerated internet myth.

If you slap a VTEC head on a non-VTEC block and never go beyond the stock redline, the motor will last just as long as before. But only if you keep the stock redline.

As far as which manifold to use the VTEC head with, the GSR manifold will be better than the LS manifold but neither one is ideal.

You will also need a VTEC ECU and some other assorted parts. It also is a very good idea to strengthen the bottom half of the motor to cope with the higher revs that are typical of a VTEC motor.