I did mine yesterday in my 147, although I did lose man points when I needed to get my girlfriend to assist to remove the MAF from the hose. I didn't disconnect the battery, I did however do a throttle reset. Only drove the car 10 miles yesterday but all seemed well. It's been said elsewhere it can take 100 miles for the ECU to recalibrate based on what the new MAF is sending it.
I'd suggest investing in a pair of Click-R pliers from ebay, makes releasing and refixing the hose clips a doodle (assuming that is what is on your Alfa)