This has been done a few times on clubgp.
Doing the swap, you loose the IAC system since it'* external on the L26 and the PCV system since it dosen't line up.
There is drilling and taping needed to plug the L26 IAC port.
The opening on the L26 UIM is circular which is much different from the L36.. So basically no matter what adapter you use with the L36 TB, the air will not flow as smooth as before.
The stock fuel rail will fit but if you run a HVII you'll need to cut, flare, and extend it.
Here are comparison pics:
For all the work needed, I would rather drill and tap the LIM so the coolant never sees the UIM & TB. Some of the guys further up north may want to keep the coolant flowing to thier TB to heat up the engine though..
My UIM is failed right now but my HVII blocks the coolant from the UIM so I don't really have to worry about it.