CF Mod: suggestions for hardware?

[squonk]

Hi!
I'm still a X5 user (very happy with it!) and I'm considering to purchase hardware component for the CF Mod.
The guide linked before is a little bit old, especially for suggestions on adapters.
I find many people on the web that made this mod, also with variations.
For example: someone use a 50-pin to CF adapter and a SD to CF adapter, and I find a 50-pin to SD adapter that (I think) can be used.

So I got many questions about this mod before purchase.
What is the best solution in terms of performance (read / write)? The only limit is on the memory card (CF or SD) or an adapter can interfere with the speed?
And about capacity? In an old thread I read about 50-pin to dual CF adapter, but I can find nothing about this...

Final questions.
Which adapter you recommended? IDE to CF? IDE to SD?
Can you also suggests some specific models?

Many thanks!