Buy the ITR if you can. The ctr motor would have to go into a very light car to appreciate it.

Don't let anyone tell you an ITR is garbage or not worth it. Besides, whether something is worth it is relative to how much money you make or have at your disposal.

The ITR is a stroked b16 and tuned in other ways for high rpm performance. It is a refined motor with valves that are lighter and thinned for increased flow. The springs are special and designed for the lighter valves and higher revs. The head is ported around the bowl area and performance cams are installed, along with coated, high comp pistons, stronger rods, narrower bearings, and a very nice, ballanced crank with more counterweights for smoother running at high rpms. The flywheel is lightened, a bigger intake manifold and throttle body are added, along with a performance header in the jdm model.

You could build a gsr to match it but would have the same money tied up, maybe more.

And I don't think there is any question a gsr or itr will live longer on average than an ls/vtec, just like there isn't any question a b16, with its far supperior rod/stroke ratio can outlive them all. You can build an LS/VTEC to hold together longer, but you can't build it to wear longer. That 1.54:1 RS ratio is a killer compared to the other motors - which is, of course, why Honda built the LS block as the lower rpm grocery getter and didn't use it as the base for its high-reving performance versions.