I think the key phrases are 'in order to gain the
best results' and 'can't say I noticed any difference
on the road'.
My added emphasis.
I say that because the intake stub modification is to improve gas flow at peak rpm and it's what allows the engine to breathe most effectively at the top end of the rev range.
On the road, most of us don't get to use the 8 - 11k rpm regime all that much. When we do, it's usually during hard acceleration in the lower gears. The rush is such that frankly, most would be hard-pressed to notice an extra 4 - 5bhp at 8k rpm and over ... everything's happening very fast at that point!
In the higher gears, holding on to wide open throttle at 120mph plus, well ... yes, the additional horses are what keep the motor pulling harder but again, it's a difficult thing to quantify if you can't compare stock with tuned back-to-back.
The dyno tells the story better, of course. Personally, having done the various mods one at a time, I found the most discernible difference was that the motor picked up revs a bit quicker after having the intake stubs modified. Again, going from stock straight to Full Monty, that's a hard thing to notice when also encountering all the other benefits of the Full Monty for the first time.
