K&N Compatibility with 6637

[warrenroadie]

I'm ordering a 6637 filter to replace my K&N filter from Riffraff and have a question. Will the 6637 filter attach to my K&N intake tubing or do I need the tubing kit from Riffraff? I did not know of filtration issues with K&N filters for turbos until I starting reading on this site.
Thanks for your help.

[Fordman247365]

As long as the tube is 4" it will fit

[warrenroadie]

Thanks, I'll measure K&N tubing to filter.

[m j]

the 6637 bolted right up to my K&N piping.
the air temp sensor bracket had to go as did the filter restriction gauge