LOL! Noone picked up the 'this is going in an MR2' bit.
Good luck fitting 1x T2 sub in there, let alone more than one.
You have three options for sub placement in an MR2 :
1) Behind the seats. This requires a shallow sub that works well in a small sealed box, probably a 10" in most cases : Rainbow Hammer, Resonant Engineering RE, DLS Magnesium, Focal Access, etc.
2) Under the hood. This works well but requires MASSIVE amounts of custom work and fibreglassing to do properly, plus you need a high output sub to get the bass at a reasonable volume in the cabin - it has to go through a steel wall afterall.
3) In the boot. Waste of time, dont bother.
If you want to put subs in an MR2 without a lot of work, its behind the seats time. Now unless you're 4'6", that means you've got around 15-25L per sub to play with. So you want small, high output subs with good linear throw that operate in a small box - Rainbow Hammer or Focal Access would be my picks, or a DLS Magnesium MW110 if you're handy with MDF and dont mind building a rather complex slot ported box