The best price I could find from a Bosch agent was £260

- So I got a Synergy and a Pierburg MAF instead.
This Bosch one on eBay is miraculously cheap.
If you disconnect a working MAF I would expect the low down acceleration to be a tad better and the fuel consumption a good bit worse.
If you disconnect a failing or poor MAF I would expect the car to feel a good bit more lively and the fuel comsumption to drop much as above.
I wouldn't bother to disconnect the battery just to change a MAF.
If the car has an auto-box then I might just disconnect it, and the car will feel quite different until the ECU 'learns' your driving style. I didn't believe this until I tried it.
S.