I saw some people saying valve job and so on. I would pull the head just to replace the headgasket!!! If you have the money do the valves or porting what ever do it. The main thing IMO is getting that headgasket done. I have seem MANY MR2's junked just from blown warped or cracked heads.If you know your gona run it hard play it safe.
Headgasket,timing belt,water pump. If you wait till things go wrong its gona cost ya big time
Enjoy the new car