most definitely, being a race car you could only imagine the r&d that went into the head work.
however, my head is ported to specifically match my cams with bigger springs but still runs stock valves/retainers/buckets.
its simple - if you want more power you need bigger turbos & cams etc
each to their own, im just vouching from what ive learnt from others that have been mucking around with gtr's when i was in high school