At 290k on my old y5 the egr passage was clogged all the way from the metal plate, to thr egr, and the egr back to the head. (The egr recirculates exhaust gas from valve overlap back into the intake manifold port)
I re used both gaskets with no problems. I had to use a drill bit that I turned by hand to clean out the ports under the intake plate. So you don't drill, you just use a drill bit
The best modification you can make to the egr system is to remove and clean the intake manifold and clean out all of the passages inside and out. You could port the holes under the plate but it is still going to pull the same amount of vacuum into the intake through the egr valve.
So it would be like running a ported intake manifold behind a stock throttle body. You might get a better intake response initially from the larger diameter holes but it will still restrict air flow from the air inlet opening
http://ecomodder.com/forum/showthrea...ean-30057.html