159 Cruiser and
AO Silver Member
Join Date: Jul 2012
Location: United Kingdom
EGR blanking itself is pretty simple, two bolts on the top of the EGR undone, and a blanking or restrictor plate (a blanking plate with an 8mm hole in it), slide underneath and the two bolts done up again.
The full blanking plate will raise an engine management light (unless a suitable map edit is made), the restrictor plate should not.
Both will be pretty dammed difficult for any tester to find unless he starts taking the engine apart, or reading the map.
I wouldn't worry about the testers finding out. It's technically also illegal in the UK (same reason as coring the DPF as you are altering parts of the car designed to let it past legal environmental laws), yet don't think a single person has been done for it (or cares). In either way, unless you bought it new, they would have to show you changed it.
159 1.9JTDM Ti and Giulietta 2.0 Veloce
ex: Punto 55s, Golf Mk5 1.4FSi, A3 (8P) Sportback 2.0TDi SE, A4 (B8) 2.0TDI S-Line, 306 HDI Meridian