Depends on your budget. I went with DA's recommended Slimline pitts (bought it with the motor).
For my current application it's awsome. I have it in a Lanier CAP ARF @ 17# and it's ballistic.
Scuttlebutt is these new Slimlines have bigger down pipes therefore flow better than the older version.
I also like the third mounting bolt and the DA supplied mounting bracket to support the can.
Hope this helps, Barry