Thinner or thicker head gasket, depending on what you are trying to do. Thicker head gasket will lower compression, thinner one will raise it a little. Also, you want a dead-soft aluminum or copper head gasket, don't go for that paper junk, metal gaskets seal better.
Also, you may want to look into balancing and blueprinting services, they will balance the crank and weighted parts, and will check to see if the engine was machined to exact factory specs, and correct it where needed (some engines leave the factory with ports, bores, clearances and tolerances a bit off, which explains some cars performing better than others from the factory) A B&B will set you back anywhere from $300-$1000+, depending on the motor and amount of work done, but will assure that your motor will be machined and balanced exactly as the enineers originally intended.
You can also strengthen up the motor, replace those studs and bolts with a set from ARP, get forged main caps made, decent rod bearings (try twins-turbo for these, they make awesome bearings for the supra engines) Forged rods & pistons w/gapless rings (total seal). When that's done, you can pin the sleeves, or get a deck sleeve ring, and make the top of the block rock-solid to reduce cylinder flexing at high revs.
Lastly, since the 2ZZ is a high-revving beast, look into lightening up the moving parts, titanium valves and valve seats with hi-performance valve springs will not only reduce valve float, but will reduce the weight of the valvetrain (lightening up the valvetrain, even in tenths of grams, will let the motor rev up faster, and free up HP)
While were on the subject of revs and making things lighter, if you plan on hard-core racing, you may want to knife-edge the crankshaft, this will reduce the crankshaft's weight, and while it's been known to reduce torque a bit, it really bumps HP, and the motor will rev up a lot faster, this mod if for hardcore racers only!
As a knife edged crank can possibly break, or you will lose a lot of torque. Only let experienced engine machinists do this for you, the person needs to know how much to take off the lobes of the crankshaft, and they still gotta keep it balanced. Definitely not for the weekend tuner!
Below is a knife-edged DSM crank, notice how it's been bull-nosed on the leading edge, and sharpened along the trailing edge. This reduces windage, as well as rotational mass. It's also less likely to froth up the oil in the pan when driving hard. A toyota crank will look different, but it can be knife edged like this as well...