I did a BL conversion of my micro-t about 7-8 months ago. I would say to not bother adding too much aluminum to the car as it will really weigh it down. Parts I was glad I upgraded - shocks (go AtomicRC), ball-bearings in the wheels, threaded axles.
Even on 2S lipo (i built a pack using 2 250mAh Enerland cells from bphobbies.com - tight fit but work very nicely and last for 40+ minutes) the Feiago motor has a lower kv rating than the stock motor, so it won't have as muh speed. You'll need to gear up with the highest pinion and you'll have some speed and great punch.
I would actually consider checking out the new micro-t that Losi just put up on their site:
http://www.teamlosi.com/Products/Def...rodID=LOSB0233
It looks pretty cool and has a slightly longer wheelbase, so much a little more room to mount things.
With my conversion (I'll post a pic tonight) I actually managed to squeeze in 2S-250mAh lipo, a Novak XXtra synthesized fm receiver (case removed), a Mamba25 esc (you have to re-move and re-solder the capacitor so that it fits - no easy task as the solder CC seems to use on the cap has a very high melting point), and a micro-servo with a 3-wire connector.
Motor:
http://www.bphobbies.com/view.asp?id...05&pid=U832265