First question... Have you ridden a Thruxton yet? You are spending money on assumption to "upgrade" something you know nothing about personally. I came from sport bikes too, literally got off my 675 right on to the (now mine) Thruxton for a test ride. I was VERY surprised how it felt. Just a ton of fun and plenty fast. Is it a 675? Nope. Can it kick up to 110-115? yep (so I've heard ) To try to pull a few more horse power out of it for street use is pointless IMO. Having said that, there are several mods that can be done to improve minor things and tons of things to improve looks, handling etc. Ride one, then go from there.