The Oil filter is not so bad to get to with the Greddy/Greddy Copy plenums. The water piping underneath (if its the stuff I'm thinking of) is a real pain, but I have never had to deal with it since I put the plenum on
It would probably be better if you could do the plenum off the car and make it all neat under there but because mine was in car and I needed to get it back on the road ASAP I didn't get to do it as neatly as I'd have liked
It's definatly alot easier to get to coilpacks etc, which if we are honest, is going to happen alot more then playing with the water piping under the plenum (Hopefully anyway )
I'm happy with the ease of acces at the top of the engine now, It looks a bit odd if you have the bonnet up and stand back from the car a bit because there is so much gap under the strut brace
There the best photos I could find, if they help at all