Got a quote from a local shop to install an alarm system with:
Marksman M9A (Lock interface, motion, 1500-2000ft pager 2 LED's & remote start for $675)

http://www.aboutsecurityconcepts.com/ProductDetails.asp?ProductCode=M9A

Never heard of the brand and havent required an alarm for 20 yrs. Another shop carries Clifford and Viper which are known to me but are $1k + for similar features.

Any input?

IMHO whatever alarm brand you get will be fine,as long as it is installed properly.Ask the installer how he makes connections.If he (or she ) uses scotch loks got to the next store. Installation is the heart and soul of an alarm.I sold and installed Carbine (maker of Marksman) years ago ,and never had problems.As to your add-ons, I've never been a fan of motion or radar type sensors.They have way too many false triggers. I highly recommend if you get one,to have a switch installed so you can turn it off. That way you don't need to leave the vehicle disarmed if it is raining,or leaves are blowing,or you have to park in a crowded parking lot.