the gsr head is not a bad choice. but personally i will always run a b16 head over a gsr. for one, and most importantly, a b16 is cheaper and wayyy easier to find for a reasonable price. two, there is nothing wrong with the casting on a b16 head, and it actually has a more efficient combustion chamber, raising the threshold for detonation. one thing you might like about the gsr is that it has a smaller combustion chamber which will raise the compression as opposed to the b16. this is a good thing if you are not swapping out your ls pistons for higher compression ones. anyway i agree with mikebergy that in itr head is not necessarily worth the money, although its not a bad choice if you can find one complete, and reasonably priced, just to save you a trip to the machine shop for a p&p. plus youll have your itr cams sitting in there for you.
also, do some research on other forums. there are a million write-ups on going ls/vtec. its really not too complicated. most important is running the oil line properly, getting a good head and cams, the right head gasket, making sure you wire up right, and get the right ecu. go with mikebergys advice and get a chipped, or a stock p28. its best if you want to upgrade or get a tune later on. oh yeah to make life easier, just buy the golden eagle vtec kit. it has good parts and mostly everything you need and is cheap