G'day. Dont trust any of the yanks on this site. It's us against them.
If trails go for the DMC 916, Toomey T5 or T6. Dont waste your money buying it brand new, just keep an eye out in the 'for sale' section and make a wanted thread of what you are looking for in the 'wanted' section.
I have the DMC 916 and I would recommend them if doing trail riding.
If you're going to be doing mostly dunes then go for the T5.
Also the T6 you've been looking at, what reeds does it come with and how much is it going to cost you?
With any air intake or power change you will need to change jets, have a look in the jetting and exhaust forum for on how to jet. Since you are going to change your exhaust, also get a K&N filter.