if you want top end power stay with OEM..the VQ35HR(m370) is great for mid-range if thats where you want it..seriously though if you can cut plastic with dremel you can save yourself a ton of money on the M370 and do it yourself.
everyone of my dynos i made more power on the top end with the stock plenum..
First Dyno with Following Mods
Berk HFC Stillen Gen 3 Ark Exhaust
Uprev tuned with Following
Berk HFC Stillen Gen 3 Ark Exhaust VQ35HR manifold
Ported stock plenum with ecutek tune