At least in the early 80's, MGA was a lower-priced line that offered primarily all-in-one, complete systems with some optional components (tape decks, IIRC). Mitsubishi was the brand of higher end, individual components and, later on, receivers. Not sure that was always the case, but it was that way from ~1980 to 1984. Also, IIRC, MGA was a separate and distinct franchise from Mitsubishi; i.e., an authorized MGA dealer was not automatically authorized to sell Mitsubishi. MGA was sold through lots of outlets. Mitsubishi was limited to specialist dealers.