pretty much u cant if u have a r33.. no one will touch them and Nistune dont make a board for them..
U have to get a r32 ecu, then nistune it, then get ur variable valve controller installed as well..
after all this is done, ur better off just getting an Apexi PFC for ur Car, and having a much better / through tune.. I know Dr.Drift does this, and he charges arround $1,200... So by the time u pay all that may as well get an Apexi for $1000-1,300 and get that tuned up
I went through the whole weighing up all the options like this too, but Apexi PFC came out on top, that is probably ur best chance of getting a good decent tune. Without all the f**king arround to do with a r32 ecu, because in the event that u get EPA'D it will be much easier to swap straight over... And you WILL get EPA'd its just a matter of time..
Anyway my 2 cents on what i did and why i did it, but best of luck to you.