Anyone have experience with the Challenger stainless oil filters?

Nobody know?

Just stay with the Rotax oil filter. You may be shortening the engine life and if at sometime you need help from Rotax you'll  be on your own. What's  wrong with just using the right one?

I quite like the idea of having additional cooling.

"They're certified and TSO'd and have the same pressure bypass as Rotax filters now."

The real question you need to look at is what is a TSO?  That simply is the filter manufacturer convinced someone at the FAA that it was suitable for use as a replacement part for a certified Rotax...it is NOT approved by Rotax and not tested at Rotax.  

First they do not have a bypass that I can find, it is just an element inside.  The element is not removable other than as an assembly so you can not spread it out and look into the fine holes to inspect, your inspection must be done with the filter element folded as you cant pull it open.  

Second, if your that near your critical level of oil temperature that you need the extra cooling perhaps you should look at some other items as the same time.  Not that it does not work or look great but that should not be the reason you buy a filter.  

Third, given the price is should have long life and on that point i get it.  Looks good, not going to buy another filter sounds great.  

Having seen engines with precursor failure materials starting to find their way into filters I am a firm believer in a good oil filter inspection.  This filter does not really do it for me as it is too difficult to really see fine materials when an engine is in early states of problems.  (like a lifter failure starting to wear away the lifter face leaving tiny bits on the element) 

Just my opinion. 

Pretty good opinion and right on.

Plus why change? The Rotax filter is easy to come by and Rotax stands behind it and if you have an engine issue especially while in warranty you don't  want Rotax to turn you away for using after market parts or open yourself up to an insurance  issue if you have an issue for using after market parts.