im surprised your dealer even offered it. My dealer said that MBs cannot be fitted with remote start (MB remote start system at the dealer), and using 3rd party systems will void the warranty.
Honestly, if your dealer is offering you the system that doesn't void your warranty, you should go for that. Im sure you have seen all the issue people have with their MLs, so you don't want to be left without warranty, or you don't want something to mess up the computer system.
Im sure they will use your 3rd party starter system as an excuse to not perform any warranty work for you.
Also how much exactly did the dealer quote you for?
