Thanks for the answers, but it made me think of a few more, I'd really like to know about.
As I read it on the other thread, for example #325, the smaller (standard) plenum volume benefits low pull, with having a peak in VE in lower rpm's. And the bigger volume in the plenum chamber with the added 1" spacer, makes the increase in VE move the peak in pull up to the upper rpm band.
Is that correct?
How does that change help street driving?
Or, is this only for added top end power, at the possible cost of some low end pull?
The next I am wondering about is the injection and the ecu on the SE/S4/S4s cars.
Does that have the ability to adjust itself with the standard jets and programming, to the higher volume Vp with the added spacer? I must be sure, that I won't starve the engine, for example!
Note, that the engine in the UK is very highly uned, with a totally different engine setup and completely userprogrammable injection system; not anything like the standard ecm and standard system/jets etc. So what is the benefit on a standard engine? (not the highly tuned one at over 460hp)?
Finally, if the spacer is beadblasted, will it be on all surfaces, or only on some, like the outer circumfery? Can gaskets in paper as standard used, make it tight enough?
Very interesting, and I hope to get the answers, so if positive, I will add myself on the list too.