I have a near-complete list of everything I have pulled off of my car. The big things are noted and you cna pick what you think you want.
Exhaust, for example, is 78 lbs complete. If the new exhaust is kept simple, that's an easy 50-55 lbs right there. Seats are very heavy as well. Lots of strange heavy stuff in the car like the mirrors and stuff like that.
Like I said, review the list and pick what you can live with. When I hear 10 second street car I tend to recommend something like "get a 2nd gen RX-7 and put an LS1 and a 100 shot of nitrous on it". But it's do-able in an MR2.
Drivetrain is VERY stout in these cars aside from CV shafts and motor mount points. Google "Mr2 Wheelie" to see what I'm talking about
Patrick