Just the exhaust is killer on Forced air or N.O.S. ( side note...* I hate the freaking fast and furious !! dam it NOS "IS" Nitrous Oxide Systems... screw the puting in periods, for every one not to rag... he said Naws!!.... are we all together on this???...COOL!!)
On a na engine you need intake !! as the racers know, Heads are important... but it is the CAM!! That is the real wizard!! The 40s are good numbers!! they will allow 12s on the right set up!! cool??
No it is not a waste of money. When you are running NITROUS or BOOST it is more critical that the exhaust flows well. It is not as crucial for NA. It will help all application's but the POWER ADDER will benefit more from good flowing exhaust.
Have you ever seen the profile of a good NITROUS or BOOST cam? Big exhaust numbers.
All I can say is stock cammed, non ported 40s have been in the 11s for a while... If it wasnt for the cost I would say 40s all the way. Even after I add GT-40 VT, valve job, and mill my E7s, I will be getting beat by the GT-40 cars this summer.
In my opinion go with the thumper's. I just had him port my heads about a month or 2 ago (maybe 3 now) and oh my god did they look different! They looked like a totally different head, the ports were huge compared to what they used to be. I threw them on my car with a crower cam and man it was a difference like night and day. I support his heads all the way. I'm gonna have t-moss port my intake in a week or so and then hopefully my car will be able to breathe properly.