I notice there are lots of us running BEC injection set-ups without air-boxes... just TB's straight to sausage-style filters. No MAP sensor.

How much does NOT using this sensor affect the running potential of the engine?

Cheers.

A map sensor would be piped after the throttle plates on individual runners.
If you are using tps in my opinion it's not load sensitive just an approximation of load using throttle plate angle.
A MAP sensor would be more accurate sensing engine load and for instance road incline.
A plenum may smooth out induction pulse
Most production cars run MAF at the plenum intake

Cheers Snapper... I'm just trying to work out what I'm going to do with the Aprilia V-Twin - airbox or not! Aaaaaand if I am using an airbox, then what sensors are worth adding...

confused.com