speed density

Hey, does anyone know the downside to a speed density 5.0? I currently own one and am considering swapping to mass air. My car also has a hard time running when i first start it up, but once it gets running and warmed up, its fine. Is this related to the speed density set up? Any thoughts or comments are always welcome.

Downside is it uses a MAP sensor instead of a BAP sensor. This makes it sensitive to vaccuum changes outside of factory specifications unlike a MAF set-up. And no ya car's prob is not from speed density and going to MAF will not fix it.

Its just a cold natured ford. Like all the rest.

speed density is a fine system to use unless you plan to upgrade the engine a lot. Small bolt ons should be ok, but the bigger things like heads and cams will be to much for the factory fuel cushion programed into the ecu. The s/d system can be made to perform as good as a maf system, but the computer needed to be programed on a dyno to get the proper a/f ratio just like the maf. I guess the s/d system just has a smaller tuning window stock then the maf.