im guessing injecting straight into the intake manifold he's after the peformance gains from the methanol rather than cooling effect?

yeah i think so.

after speaking to a few garages and people in the know, the reason the best placs for injecting the mixture is 6" or more before the throttle body is something today with the IAT sensor being there. it allows the mixture to fully atomize witrh the air and cool it down before the senor. he now has them both. its probably a bit overboard what he has done there, snow performance reccomended a big nozzle at the bottom of the throttle body/intercooler pipe and a small nozle 6" below the TB.

Read somewhere that for every degree you can get the inlet temps lowered by is equivalent to a couple horse power gain