The head. Let's first start off with your choices. There are B16 heads, ITR heads, and GSR heads. IMO, it is never worth buying an ITR head, if you plan on upgrading the springs/retainers/cams anyway. They are amazing heads from the factory, but B16/GSR heads can be had and built for far less. ITR/B16/92-93 GSR heads are built from the same exact casts (PR3), while 94+ GSR heads are built from a different cast (P72) which is why the intake manifold bolt pattern is different (from here on, 92-93 GSR heads will be referred to as B16 heads). ITR heads have a slight hand port job on the intake side from the factory. They also have stiffer dual valve springs, as well as slightly higher lift/longer duration cams and lighter valves. If you want to make more than 200whp with your lsvtec build, you are going to need better cams and springs/retainers anyway...so do you see why it's just not worth the $1000-1200 price tag on a used ITR head? The question you SHOULD ask is, should I get a GSR or B16 head? Tough question. Here's the deal...B16 heads share the same bolt pattern as ITR's for the intake manifold. They are easier to find aftermarket intake manifolds for than GSR heads, as well as being able to bolt on an ITR manifold. However, GSR heads have a distinct advantage over B16/ITR heads. Although having slightly smaller combustion chambers that raise compression is an advantage, it is the reason why it raises compression, that is the REAL advantage. You see, GSR heads employ flat surfaces in the combustion chamber called "quench" pads. They do raise compression, but the real advantage is this design's ability to deter the possibiltiy of detonation, promote better flame travel, and aid in cooling. Beware though, if you plan on running a GSR head with CTR pistons, there is not much room for mistakes. The clearances are tight. I wouldn't personally run that combination w/ stock cast pistons anyway. So keep that in mind. I personally like the combustion chamber design of the GSR head better. But, I also like the ability to be able to run a P73 (ITR) intake manifold on the B16 head. Now that you can see the advantages of both heads, it's really a toss-up. It's your decision, go with the one that suits your preferences.

Now, if you have the money, and you want to build a powerful setup, I highly recommend sending your head out to one of the many reputable head porters out there like RLZ, portflow, DonF @ DFE, Headgames, Import Builders, or Alaniz. These are just some of the more widely known, but there are some very quality smaller head porting operations going on in H-T. I've seen some of their work and I'm impressed. I would also go ahead and at the very minimum pick up new OEM valve seals, if not aftermarket. These are equivalent to piston rings for the head, as they seal oil out of the combustion chamber. Don't worry though, Honda valve seals are still fine. Valve springs and retainers are also a mandatory upgrade if you ever plan on making power passed 8k with your motor. Companies like Rocket Motorsports, supertech, omni, RLZ, Import Builders, JG, etc. make some great components. I went ahead and milled the head a little just to freshen the surface. It is by no means necessary. But, keep in mind that if you do it, your cam timing may be slightly affected, as well as your piston to valve clearance and compression ratio. Be careful how much you take off.