recommend Mechanic in Rockville,MD? and a few other simple ?'s

"brand new" owner of 1986 300 SDL. Need good independent mechanic to put me on the proper maintenance schedule and fix a few "little" things:
1. vaccuum leak causing run-on after key turned off
2. rear window inoperable - after removal of door panel discovered broken plastic thingie connecting mechanical arm to bottom of window
3. clock
4. proper maintenance schedule
5. tune up, is it the same as for a gas engine? what should I ask/look for?
6. what does 300 SDL mean? what is "126"?
Any suggestions would be appreciated.
Thanks in advance.
Curtis A.
by the way, if anyone has an Allante, there is a great board at http://www.allante.org/BB1