Re: GROUP BUY: Upgraded wires and plugs
First, they do not offer a 10mm set for the Mercedes vehicles.
Second, you can typically expect 5-8% increase in fuel economy depending on mods.
Ignition upgrades are really felt if: the stock ignition system is not adequate or you need to change plugs/wires anyway. On a stock car the best you will see is 3-5% better fuel economy, more linear power delivery, and a smoother idle.
This is not a seat of the pants mod. If you are running higher boost, nitrous, or ECU tune then this is an affordable upgrade to further enhance those modifications.
Anthony