my car was breathing better than his with the decat, straight through exhaust. but it seems right normally there's a difference of 5-20kw between neo and non neo rb25! but the difference was powerband, mine boosts quicker than his but ran out of puff at the higher rev range while his car ate mine at that point, it felt alot more punchy at top end
but i think the extra bit of torque and power comes from more duration and lift from the cams! i'm not sure how vvt works but i think the cams twist? like how v tech kicks in! i could be wrong but that's my guess