Tuners

An obvious 10hp boost if you put the sticker on your back window.

I bet the dongle doesn't do as much as the sticker, it's just there to make you feel better.

 

i don't see why not

 

I would be surprised. Toyota ECUs are locked. Most people don't spend the time to unlock the ecu unless its a mustang or a camaro with a million people wanting to pay for that ability so it pays off. 1% chance that works.
But... You can alter the signals outside of the ECU no problem. Although I run without EGR and get better mpg than most of our members so I as an engineer love the idea of EGR it just doesn't do much in the real world.
Off the top of my head altering the MAF housing size will change AFR outside of closed loop, but in closed loop the ecu will catch on and reset the AFR back to lambda. Going lean and increasing EGR is also pretty dangerous for operating conditions as well. So don't burn a cylinder