You may be interested in the branch campuses of the Deutsches Museum in Munich -- Verkehrszentrum (U4 or U5 to Schwanthalerhöhe station), which features all manner of ground transportation; and Flugwerft Schleißheim (S1 to Oberschleißheim station), for things with wings. Just a short walk from Flugwerft are the colorful - and relatively untouristed - Schleißheim Palaces, summer home of the Wittelsbach family.
Photos here.
A decade-long renovation project has just begun at the main Deutsches Museum campus on Museuminsel. The museum will remain open, but many of the larger exhibits there may be closed at any given time. All of the aircraft displayed at the main campus (except the large Ju.52 transport) are being moved to Flugwerft Schleißheim.
Do not miss the new NS Doku-Zentrum, which just opened last May on Briennerstraße, on the site of the Third-Reich-era Nazi headquarters building. Next door is the Führerbau (Hitler's office building), where the 1938 Munich Accord was signed. That building is now the High School for Music and Theater. Historic Königsplatz is across the street.
Of course there is the BMW complex, with factory tours, an excellent museum, and the free BMW Welt. Cross a pedestrian bridge to Olympia Park and the Olympic Tower for a spectacular view of Munich and environs.
do a quick self paced walking tour of down town (RS has one you can download and listen to I think).
Yes, the Munich walking tour in the RS Germany guidebook, and in the podcast, is excellent. It can take anywhere from two hours to two days, depending on your level of interest and curiosity.