Just some feedback on the subject, TD5 Discovery 2. (2000)

Replaced centre muffler with straight pipe. (Terrafirma part off eBay)
No noticeable change in performance or response, louder deeper sound but not significantly so. Performance benefits may become apparent when combined with other mods, but by itself I could measure no difference.

Next, complete EGR removal using kit off eBay, and instructions here:
www.discovery2.co.uk /workshop - EGR removal

Absolute performance (0-100 and 4th gear 80-100) measured by a VBox is no different. There are bigger differences between runs, probably as the turbo and intake temperatures changed throughout testing. Road and weather conditions were constant. You could argue that 0-100 times were up to 0.5s better in some of the runs, but this would be within experimental error.

HOWEVER, very noticeable difference in throttle response and driveability. It does feel as though the turbo picks up quicker, and the RPM rises slightly faster than before from idle. For that reason alone I would call it a win.

One note though, when only removing and capping the one vacuum hose between the solenoid and the EGR as instructed, I noticed that the solenoid sits there buzzing loudly, and even continues to do so for a second after shutdown. Does not sound healthy or sustainable at all. Therefore I removed the second feed line and capped off the T connector between the vac pump and brake booster. Now the solenoid is quiet, and I obviously still have brake vacuum.

Regards,
Scott.