Well heres the sitauation. The ideal setup is close to the head (not sure what the consensus is on what cylinder) and before any catalysit. In my case is is possible to take care of the second requirement since I have no precats, but for you that's a different case. For the first requirement, things get more complicated. The front bank is the only one that you "MAY" be able to drill into without removeing the manifild from the car, but you still have pre-cats so I don't think metal shavings falling in tere would be too good. Since I have headers I could just drop the y-pipe and let them fall out, but then you stil have the problem of welding in the bung in such a confined space.
You can still run this after the cats, but If I were going to do it all over again that's the way I would do it, but that won't happen since I think I'm done tweeking the car and it's time to save for a new toy (thinking S4 with AWE turbo upgrade and KW stage 3 coilovers).
