Perhaps of interest to anybody with a diesel engine or the 250 petrol engine. Because of their very close association with the German tuning firm Brabus, my dealer tells me the fitting of their D3 or D4 tuning box will NOT affect your manufacturer's warranty provided it is installed by a Mercedes approved workshop.

They appear to work as a signal hijacking and modifying box thereby leaving the original ECU unaltered and are consequently unaffected by firmware updates unlike other tuning solutions. They claim to raise torque by around 50Nm in all cases but cost an eye-watering £1300 in the UK plus an hour of workshop time to install and dial in.

The fully skinny can be found on the Brabus website here:
Tuning Kits for GLC

 

Most of these plug and play are very simple to hook up and usually take about 10-15 minutes max. But, they also can violate the warranty.

 

I have one of the Brabus Eco PowerXtra kits in my wife's C220. The torque improvement is certainly noticeable compared to the factory specification.
The Brabus kits are certainly expensive. They add a plug and pray computer to the cars ECU.

Brabus also provide a warranty covering the kit and vehicle if installed by one of their accredited agents.

 

Thanks for the information, Penn. I can see this unit being a viable option for the 220d owner given it will raise the output power to that of the 250d for around the same supplement Mercedes charges for the higher output variant. It still falls short on torque though by 50Nm so I guess the Brabus kit will give the same top end speed but not the quicker acceleration of the 250d unit.

 

A Brabus equipped GLC 220d will drop its 0-100 kph time from 8.3 seconds to 8.0 seconds still not a quick as standard 250d.

A standard 250d does 0-100 kph in 7.6 which drops to to 7.1 seconds when Brabus equipped.

Money would be better spent purchasing the GLC 250d and avoiding the insurance issues the Brabus upgrade may cause.