Just read your post, I purchased my 2008 Tiger about six weeks ago totally stock, firstly it felt like it was hunting whenever I wanted to run on an even throttle, below is what I have had done so far:
1,Triumph dealer loaded latest map, = no improvement
2, Then tried TOR map = no improvement
3, Triumph dealer fitted new plugs,airfilter, balanced throttle bodies, std map = no improvement.
4, Went to a Dyno tuning company, it was running very lean on Triumph map, so wrote a completely new map, graphs now show very smooth torque curve, air/fuel ration very linear.
But now suffers from the symptoms describe in your post, feels like the chain is grinding, very viby when cruising at motorway speeds.