[chrisbalich]

I'm pretty sure the AFM on Motronic has a barn-door style meter.
Assuming that's correct, replacing that with a MAF or ITBs will decrease inlet restriction and drive up power.

The real magic of ITBs is the throttle response. To my knowledge, there is no single TB system that has the snappy response of a multi-throttle intake system.

It's also worth noting that there are trade-offs.
In particular, tuning part-throttle and transients is much more complicated (and time-consuming) as much less throttle pedal input results in much more air in the engine relative to a single TB.
The difference in air volume consumed between 20% and 30% with a single TB is a lot.
With ITBs, the difference is much less.
These are functions of the increased throttle throat area when going to six throttles in lieu of one.