Without proper diagnosis, it's hard to tell.

I would venture a guess that it's the crank position sensor. A bad MAS won't prevent the car from starting, but on-road performance suffers.

Although when mine had hard start issues, eventully the fuel pump died..and the light came on. The pump and MAS had to be replaced!

__________________
2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car