Thanks guys for the great info! It's the most informative answers I've seen for power loss with larger tires. Most guys just suggest to regear and run larger tires... with the economy slump, I can't afford to dump cash on regearing yet. I just need to get rid of the crappy 14" wheels!
I ran the Procomp 17" wheels today, as soon as I reached 55mph on the highway my check engine light came on... I checked the code and it showed "fuel mix was too lean". I'm sure it was the 32" tires and wide 9" wheels that were causing the engine to work overtime and I'll check the fuel filter too.
The wheels fit nice, I cranked the wheel while flat and on a high curb to check for rubbing... none so far. They do stick out a bit, so I doubt they'll stuff during full compression, but they are a great deal and they'll get me past the 14" wheels! They'll work for some light wheeling in the desert.
The 4.75" BS is common on Tundras, so it makes sense why the previous owner ran them... they work well on the Runner. The Procomp wheels are also aluminum, so it'll save some weight from steels.
Next thing to come off is the brush guard...