GranTurismo by LeoVince on my GTI

[agilebda]

Well...... Today I purchased a GranTurismo Exhaust for my GTI 125. I was not too impressed to say the least. The stock exhaust and the 4Road exhaust run a heck of alot better. I lost about 15kph on the top end. This exhaust takes alot longer to get to top speed. I already have malossi variator with 10.5 g rollers. This exhaust seems to want lighter rollers.
I am not too impressed and find that the old 4 Road exhaust are much better for performance. I am going back to stock exhaust.

[wordslinger]

...any exhaust mod requires at least a plug chop or two..

..so you know your fuel mix is still spot-on...

..also, might require some cvt tuning to keep your engine output stable....

[MotoRandy123]

Well from Leo Vince "guaranteed performance-level"
Call them up and tell them your not getting the performance!

You scooter is fuel injected so not much adjustment can be made to suit
the pipe. If it is slower to accelerate I'd imagine it makes less power.
It could be tuned higher to require lighter rollers but I'd think they'd
recommend a change in the manual with the pipe. They're probably
hoping your butt dyno tells you it's faster because its a bit louder?

From Leo Vince;

Superior look, exceptional design
Perfect balance of innovative design and applied technology
Easy to fit, innovative look, guaranteed performance-level
Quality 'works' finish ensures increased product longevity
Latest innovations through substantial expertise within the racing scene
Unmistakable athletic bike soundtrack
ECE-Homologation for road use in the EU
Straight slip-on fitment, incl. pipe tube and mounting accessories (only if required / applicable)

[Wiz]

You have to learn to read ad-talk (A lower form of lawyerese)
 
From that quote they are not guaranteeing a "high" performance-level but just "a" performance-level in a general sense. A very poor performance-level is still a performance-level.

In other words all they claim is that the scoot runs with their muffler not that it runs better.