Here's a dilemna I've never quite understood.
Deus Ex Machina - Gallery / 904 Thruxton
Someone buys a Thruxton, then spends at least another 8 grand or so, to end up with a bike that looks very much like a Street Triple, or a typical modern naked sportbike. Why?
Why spend all that time, effort and money to end up still with a <100 HP mid-performance bike that is possibly stressed out structurally and mechanically.
The Street Triple has been tuned from the factory to have mucho more performance, looks almost exactly like the end result of the restructured Thruxton, and has the framework, brakes and bottom end to easily handle the +100hp from stock. A few mild mod's on the Speed, and you've got a real bike?
Yes, I understand the love of tinkering, and the challenge - there are many Royal Enfield Bullet and Hinckley Bonneville folks out there doing just that - but to spend all that effort, time and money seems fruitless. Note that you'll never, ever get that invested money back. At best, you may get 5-10% more than the Bluebook listing. Pluis - oddly - these same Triumph owners always say they love the "classic" look. Huh? Then why turn it into a modern naked sportbike. Compare the photo above to say a Ducati Monster as well. Same thing, but the Ducati has way more performance, and for less money overall. And a warranty to boot!
Arguably (!) the curve is set nowadays at about 100hp as being the bottom end of the HP/Torque limit, if you are to refer to the bike as a "Performance" model, and some of these entry level style bikes can only barely reach that with an unbelievable amount of modification and huge influx of cash. And... the off-the-shelf sportbikes usually weigh significantly less.
I suggest politely that a person always should buy a bike that is at least about 95% near the performance level they seek, for the structural and economic reasons noted. A few minor - and practical - tweeks, and you can ride forever.
Ride safe (and Smart!)
Bob
Footnote to this post: My two sons, 26 and 25 yrs. old, ride also. I COULD say that I own a Honda CBR600RR and a Suzuki SV650, as I "helped" them purchase these bikes in 2009 and 2008 respectively, but be that as it may - The CBR600 has tons of mods - re-Mapped, Fast road cams, gas flowed heads, aftermarket cans, suspension work and much more. All installation work and head-work done in-house. Total investment? Maybe $2200. We use this one for track days at Balckhawk Farms Raceway. That said, If I want to go super fast, I always have this option. My Bonneville has a highly modified Air Intake Silencer, which now acts somewhat similar to an Airbox, carbs re-jetted, P&P heads, intake manifold, and spacers, and baffle-ectomied cans. All done in-house, total investment? Maybe $400, mostly in replacement gaskets, dremel tool bits and velocity stacks. I like the Bonnie for what it was originally designed for: Tooling around the backroads and twisties, shorter trips, fun outings, etc. The CBR would run circles and then some (after a lunch-break!) around even the highest of modded Bonnies, no doubt. Point is: Instead of dumping another $8 grand into an $8 grand bike, buy another, real high performance bike as a spare for when you really want to experience "High Performance" and speed. Add to that - try it at the trackday outings, where you can really open 'er up... legally! Bob 
Thruxton / Street Triple?
