I think some guys on Turboford are running LA3 with SDS tuners.
Some guys are running the 89 and later factory mass air systems with a 94 Mustang 65mm TB.
DO NOT BUY BAMAFUEL. There are a number of customers on Turboford who have prepaid for the $600 unit and have not gotten them.
Until the current crisis with Bamafuel is resolved I would avoid it. Hopefully things will be resolved soon because I am wanting a Bamafuel for my Stang.
Turboford has a number of threads about mass air conversions. You can actually do it with any of the 2.3T ECUs and a chip; it's not limited to the LA3. All it boils down to is changing the ECU's VAM transfer function data to match that of the MAF.
As far as the actual data processing and hardware control limits of the LA series ECU.....there is a ceiling for the mass air flow and injector size calculation, but I don't think anyone has made enough power to really outrun the hardware of an LA series. Just for comparison's sake, the MegaSquirt-I processor uses an 8mHz clock speed just like the LAs. The MS-II is even faster.