Engine management performance chip for ML 270 cdi

[Duncan.ml]

Hi There,

Has anyone had any experience with engine management chip upgrades to increase power and fuel economy?

I've been having a look round on the internet and there appears to be loads of companys out there offering this service.

I'm just a bit concerned as to whether it actually works and also if it has any damaging effects to the cars engine and reliability.

Any ideas anyone??