In the more modern turbodiesels the ECU or boost controller has a logical interlock such that when you disable the EGR system it cuts back on boost. Many newer gas cars will at least trip the check engine light and some might go into a limp mode if you disable the EGR system. As for the mechanics of it, it's purely an emissions control device. Disabling it will have no detrimental effect on the engine. That's kinda why they have to fabricate a negative effect to disabling it.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD