Leo Vince makes a 4Road exhaust for the 300 GTI for its European market. I've written them to find out whether it will be available in the U.S. I've had excellent experiences with their products. I have one on my Vespa 300 GTS and had one on my Burgman 400. It's lighter and sounds much better than the stock pipe and there will likely be some gain in power. Does anyone have any info on this exhaust?
Other then gain in power being unlikely, not really.
Most scooters don't react well to aftermarket exhausts without intake mods AND variator mods.
In the end, if you put the stock exhaust back on, I'd be surprised if you notice any difference, as the most
differences are in the CVT. There's no denying the weight saving though.
p.s. Remus makes an exhaust for the Downtown, I'd be surprised if they don't have one for the People.