wow the credit crunch hits, and now this is a HOT TOPIC.
Mr 20" RYMs, Where on earth did you get this idea i wonder?

i didnt find your Ebay EGR

but i did find http://cgi.ebay.co.uk/BMW-EGR-Diesel...1%7C240%3A1318
which is pretty much what i have fitted to my car 2 years ago
and bmw, rover, landrover, have been in bed u kno guys, so sum cars do share the bmw engines.

i had a look at that dodgey site you found & stayed the hell away from tuning boxes, and fans in my airfilter..
as for tuning, i wanted dyno proof like i had on my mk4 Golf GT PDI

i used ebay, to find places with rolling roads, rang them up and asked if they had the equipment to connect to my OBD. (try it the other way round if you fancy being on phone till next year)
i found a place in Watford that did me A CUSTOM RE-MAP for under £250 back then for my m47 engine,
He tested my car on dyno,
loaded a generic map for my car and tested again,
then cumstomised it to how i wanted it whilst i stood next him on the computer,
then tested it again on the Dyno.
i have the graphs to prove it, for example i know that i get exactly 100BHP at just 2000RPM. and i know when to shift to get maximium acceleration.
sounds dumb, but alot of people get it wrong in diesels

i could have had more power&torque but it would stress my already old Turbo.
back then it'd 150kmiles under its belt.
now its got 183kmiles still strong.

the guy clearly knew his business from his knowledge, but, the carpar was half full of drift-spec cars, S2000, skylines, and a few other rice poppers, 4-5 were stacked. one ferrari, and two Vauxel carltons.

The carltons were their fun cars with welded diffs, so him & friends could mess about.
And he told me that i can weld my diff, even iff i normally use it as a road car, as the negative effects are hardly noticeable.

He also agreed on the EGR subject.
i'll dig out my dyno graph and get their details on here by 2moro.

oh and if you want a dump valve then the Derv doctor in Derby can do it in a day, while you go to Alton Towers (short cab ride away), but wait till it gets a bit warmer.
i was gonna do it on my mk4 golf GT PDI but then i got hit by an OAP, and stacked it.