What services you can expect from Benz service center ?

I used to have Jeep Grand Cherokee(I still do) and I hardly visited the Jeep service center.
I changed oil at Valvoline.
I changed tire at NBT.
I installed new stereo and speakers myself.
I changed light bulb/battery/etc myself(which I think I still can do with Benz but not sure if that is recommended).
I have very detailed maitenance manual and virtually I know every nut and bolt of my Jeep (except for some complex electronics).
After the warranty expired, I changed whole suspension system and installed mod chip and stuff, etc, all done by myself or non Jeep service center.

But with Mercedes Benz, I am not sure what to do.
In a word, I feel like I am some clueless nuvo riche(excuse my french).
Someone mentioned that he installed aftermarket stereo at Mercedes service center, so does every Benz service center do that kind of stuff(installing aftermerket parts) or did he have some special deal/relation with the mechanic at the center ?
Well, because I am thinking of installing aftermarket CD changer and I don't think I can do it myself this time.

Maybe I should have bought something less electro-mechanically challenging vehicle or some other brand at more friendly place(the sales person was very polite and all, but the whole environment at the dealership gave me a kind of uptight vibe), but what is done is done and I would like to ask you some help. It is better to be embarrased in front of you guys than embarrased face to face at the service center.
So what kind of service can be expected from the Benz service center other than scheduled maintenance ? and what kind of service is ok for other service place(non benz service center) ?

Thanks in advance.

honestly, a good MB service consultant should be able to help you with just about any aspect of vehicle ownership, or at least refer you to some one who can. it of course depends on your relationship with your particular consultant. i try to work miracles for my customers as much as possible. we are of course in a highly competetive market, and depending on your location, you may have a different experience. just be cool when you go in. i deal with a lot of clients who are not always the most polite, so a smiling face that does not expect the world handed to them on the back of my first born is always welcome. besides, there is a standard that goes along with representing this brand. i think you have little to worry about. as for when to visit the indies, i wouldn't recommend having much done there (especially on later model vehicles). these cars are highly specialized and a lot of what is conventional automotive wisdom does not necessarily apply to them. and if you do go to the indies, make sure they are at least getting you MB parts.

What is the year and model?

In California, there are lots of MBZ gurus on the 70's-80's models, but out in Minnesota, there is almost nobody that knows my car. Thankfully, I learned most of what I need to know back in CA.

Depends on where you are..what the mechanics are familiar with.