Gonna be putting on D & D pipes, 3: 1: 2: What would be the best triumph tune to install?? should I change underseat filter to K&N??? Wanna keep the best fuel mileage also.
I don't believe you'll find a specific tune for an underseat K&N; but, I don't believe there'd be much difference, if any, with an undertank K&N. The underseat K&N has been on my tadu list.
On the otherhand, leaving the fresh air duct in place under the seat may be an air flow limiting factor that will negate any improvements with the K&N. I removed the air duct for other reasons.
I would probably run the 20150_1 tune from the Tuneboy page. There are no custom tunes for D&D's out there, but this should get you in the ballpark. You might get some decel popping but that can be taken care of.