Be careful with the load on the wiring. If the 650TR wiring is anything like the wiring on the Jetmax then going with 55-60w Halogen should be okay, but anything more than that - not a good idea. HIDs are likely a non issue in terms of wiring load on the 650TR.
I first swapped out my 35/35w OEM Halogen's on the Jetmax for some imported 90/100w, which while super bright, did put an obvious load on the wiring. After running the higher wattage bulbs for a time, I removed all the tupperware to inspect the wiring to find that the connectors had melted and were somewhat deformed. I swapped down to imported 55/60w Halogens, and also bought replacement wiring looms both for the headlights, and the Jetmax's main wiring loom just in case I'd done more damage. It didn't take long though to swap the 55/60w Halogen's for a set of 25w HIDs. I tried at the time to source 35w HIDs but none were motorcycle specific in PRC nor available. That has since changed and I recall seeing 35w motorcycle specific available on Taobao.
The problem with the HID's via the majority of the Chinese manufacturers available in most bike shops/sellers or on Taobao, is although very bright, the beam is widely scattered/distributed so even low beam can blind other road users, no matter what efforts one takes to adjust the headlight accordingly. The ultra white light 4300K of HIDs is also not as good for the human eye, which is why Halogen bulbs generally have a slight yellow hue. This assists the human eye to pick out shapes and shadows (contrasts) etc. Bright white of HIDs seemingly provide more viewable light, but after driving/riding using them, all the light tends to "wash out one's vision after a time". Notwithstanding that HIDs used during rain and very wet conditions seemingly provide less light than Halogen.
I've looked a little at replacement for the 650TR headlights but have found that H8 bulbs only seem to go up to 35w. I did see reference some place on the net that referred to H11's but I'm unsure if the H8 and H11 bulb design share the same base/connector?
Read this discussion on the
Aprilia forums concerning H8 - H11 conversion