I'd 2nd the valve springs. And like to know what kinda plugs he put in. If Boisch platinums, stop right here and get rid of em.
As for the new MAF, what does the body of it look like? Is it straight, or gourglass shaped? If hourglass shaped it is the WRONG one, and will lean the car out at somewhere around 180gps.
What was done (if anything) to the car PRIOR to this problem starting?