RE: fg big power pipe ?
There is a slight difference but not enough to justify the price, but I would recommend either the samba 5 or even better samba 6.
Also check ebay, there is a samba 5 up for grabs now, used but at a discount.
You can also if you want to find a good selection of onroad stuff, search ebay under ebay.uk section and other over seas areas for guys that will ship to the US, there is plenty.