Understood.....I certainly didn't mean to offend anyone.

It's more or less just a interest then anything else. I'll post results if I attempt anything. It will of course be for off road use.

I just sold my 02 TDI loved the car didn't feel like doing a timing belt every 80k though. Check out the TDI Forum and the Epsilon device. However this Mod would actually work on the TDI since the EGR Valve is closed when the manifold boost exceeds that of the ambient air. So Turbo or not it is possible

As for your 99, you could chip the car, it should make serious mods to you EGR operation, check out upsolute. Their ECU chips run around $350 installed and are impressive on turbo powered cars, had one in my TT went from 225 hp to 252 hp and 280 NM 338 NM.

A 99 Mercedes E300 will go from 177 hp to 205 hp and 330 NM (243 ft / lb) to 378 NM (279 ft / lb). Yep 280 ft/lb's of torque. And increased MPG too!