As I understand it, the purpose of a less restrictive pipe is to allow the engine better scavenging and therefore better breathing. If you are cramming the cylinder with air this becomes a moot point.
This is true, but a free flowing exhaust would still help. But yeah, with all that extra air/fuel charge getting rammed down it's throat, I can't imagine that there's too much burned fuel mixture hanging out in the cylinder.
I wouldn't hook a garden hose up to a 4" pump. If you can't get out what you put in, it defeats the purpose....do a little search on cylinder and intake tract reversion. That whole setup looks a little funky....
