This is what i was saying. get a builder that 'knows' how to make them work if you want to use GT-RS'
The correct cam selection, port job, secret squirrell stuff, that usually isnt revealed, to make things work.
The guys with years of experience building and tuning similar/different combos will make them work.
oh and $$$,
If your builder hasnt had the experience to make them work, you will just end up with a not so good result with them, where as the -5 would of achieved a similar feat.
we can tell you to put 290 degree cams in it, but if they dont match the specific port/head work. its pointless.