hmm , me and flyspyder55 are finishing a na-t in a mk4 rite now , its a complete rebuild with 2jz turbo pistons , i would say that is the way to go after comparing the two pistons first hand , now i see why u can make 4 digits on a stock bottem 2jzgte , also i would go with a side exit intake manifold as it will elimate a mile of intercooler piping , also the desighn of the ge manifold is pretty crappy , but hey this is my first mk4 i've ever done , as i am a honda guy , but flyspyder55 is a wealth of every little bit of useless toyota information that could ever be fathomed