Hey, I'm taking ownership tomorrow afternoon of a Galaxy Black Beauty, 4x4, with offroad, tow, dvd (for the kids)

, tool box , and lsiding bed extender. I calculate MSRP to be $38,990 (invoice of $34,994). My deal comes out as $35,176 plus $2,100 txes etc. (which is low - the dealer took off their $650 handling fee) to come up with the payment I wanted.
Help me out here - I Three questions:
Is this a good deal? I figure all said and done it's about $500 under invoice.
Should I get the extended service plan? $1800 sounds like a lot figuring I drive 22k miles a year and will be out of the coverage in 50 months or so.
With the problems some have had (noisy dash, brakes, rear diff, etc.) should I walk away and not make the deal?
Thanks
HDGreyRider