For anyone seeking a bit more throttle response in their CRD on the cheap and as part of routine maintenance, check out Wix air filter 42843. This was used primarily in Chrysler and Dodge vehicles built in the 2005-2010 era; engine sizes it was applied to varied. FWIW, this very likely also applies to V6 models, but as I don't have one I can neither confirm nor deny the accuracy of that supposition
For comparison, the specs on both the stock KJ filter (Wix 42329) and the Chrysler / Dodge one (Wix 42843) are as follows:
Wix 42329: Stock filter. LxWxH: 11.45" x 8.28" x 1.6" (291mm x 210mm x 41mm). 298 CFM flow rate.
Wix 42843: Chrylser / Dodge filter. LxWxH: 11.4" x 8.28" x 1.6" (290mm x 210mm x 41mm). 352 CFM flow rate.
Dimensionally, they're virtually identical, but the Chrysler / Dodge filter flows almost 20% more air than the Jeep one. Pricewise, they're about the same in the places I'm looking.
I've run one in the CRD for about 18,000 miles, and while it's due for replacement there doesn't appear to be any additional dust, etc. making its way into the intake hose. About half of that distance was running in a V6 airbox; the other half has been in the CRD airbox. Can't make any claims to improved fuel economy (it's certainly not any worse), but the butt dyno says throttle response is noticeably sharper.
If you're interested in checking Wix' specs for the filters,
this link should bring up both of them. They do cross-reference with other manufacturers' part numbers, but that is left as an exercise for the reader