Chugger SS replacement Head Question

I'm considering upgrading to the Chugger SS heads to replace the polysulfone heads from my March pumps. I have one regular March and one high flow March. I've looked around at different vendors who offer the replacement heads and see that some look to include the impeller and some don't (or aren't pictured). Do these replacement heads come with impellers? If so, are they the high flow impellers? Also are center inlets with reducers the way to go? or just stick with my current arrangement and get the in-lines? Thanks

When I bought mine (from Brew Hardware) it included the impeller. The chugger impeller is "medium flow", meaning it's smaller than the March 815 impeller but larger than the March 809 impeller.

There's no right answer on center inlet versus inline. The center inlet have a slightly higher flow rate, but many people prefer the hose layout you get with an inline. Personally, I use center inlet.