I would dump the underseat K&N, follow the How-to Forum's thread (on this site) to install triple K&Ns/remove secondary plates from your throttle bodies, and then have your Triumph dealer install a different base tune map.
You can do the K&N conversion/secondary plate removal for the cost of the three K&Ns, about $120 total, plus the cost of five feet of radiator overflow hose, about $4. I'm mechanically "brain-dead" and successfully did the whole job in two hours.
The Triumph dealer will charge probably less than $60 for the new tune. Then later maybe you'll want to have your bike dyno tested so you'll know your hp and torque figures. Or shoot the wad and have a dyno shop tweek you tune map for optimum performance.
Tell me about it.Come back from wales last sunday.It was like being on a jet ski.Good fun coming out of the roundabouts and spinning the back wheel though.