E46 320d few questions

I need to get swirl flaps blank as mine are removed but not blanked. How do I know which one ?

Also I'm looking to replace vacuum pipes as there is an issue there. Like misfire between 1300rpm and 2000rpm when lightly pressing gas pedal. Was not like that when I bought car. After air filter change started.

Can I use any vacuum pipes the same diameter? Or has to be special?

It's 2004 m47tu 150hp euro4

if something happens after u did something , just double check everything again ! maybe u didnt fit air filter correctly .
it should be small flaps in that engine . most correct diameter hoses are ok .get 4 round and 4 square inlet manifold gaskets as well

Thank you.

I've ordered 22mm blanking one with all gaskets.

I'll get 10m of the vacuum hoses as well the correct size one.