The speakers are the same whether Burmester or not I believe (a bit shyte).
The number of speakers changes depending on what system is in the car (more speakers the higher you go).
The difference is as stated with regard to the largest speaker is there is only one woofer in the passenger footwell without Burmester.
It's 6.5" in a C Class as well which is not great news (a smaller speaker has to move much further to produce the lowest frequencies, which when coupled with a low power amp means quicker distortion!).
The amp definitely changes though. Burmester-only gets a Burmester amp with their "settings" - Audio 20 will use whatever generic audio amp is cheapest probably knowing MB.
The "Front Bass" setup is just that. Not really subwoofers, although they handle typical subwoofer frequencies, and a shallow installation.
Theoretically, you could run a second woofer by splicing into the existing passenger footwell woofer channel.
However, it's whether the stock generic amp is powerful-enough to drive it well-enough (which it probably will although that's not good news) and whether you will get much benefit from it i.e. if it's worth the cost and effort - I seriously doubt it!
If you want more bass and are looking to limit costs, you'd be better off running a signal cable from that same passenger footwell woofer channel to a high-level input on an active subwoofer or amp and passive subwoofer.
If boot space is required, you can remove the sub if you wire it with banana-plugs or similar.
There's no coding involved at all because once you get to speakers, you are beyond the MOST fibre-optic ring although if you do go down the route of running in an additional amplification and / or subwoofer, you may need to fit a load generator module to "fool" the stock amp into thinking the correct speaker is still attached.
Depends what you want to achieve really.