Jeff,
I disagree with the above, I bought the HMEC-25 ANR on ebay (£180) and have had absolutely no problems with them and excess noise even when for one flight I forgot to switch the ANR on. In my experience they are a very good and are not heavy or too tight like others that I tried.
I have used them in 2 different PA-28-140 and 2 different PA-28-161's and found them comfortable with the audio very clear and never had readability issues with ATC. With the ANR on enough engine noise comes through that you can still judge RPM by ear. Not sure how the DR400 compares noise wise in the cockpit to the Piper's, might be best you borrow some first before investing.
Cheers
Jof