The Uniden R1/R3 normally doesn't have much trouble with Mazda BSM pollution.Until you get stuck behind them on a 2-lane road with no passing zone. Happened to me yesterday behind a CX-5 for 10 miles. Detector kept unlatching and re-alerting, so pressing mute was futile.
Honestly, the only thing preventing me from getting an R3 right now is the filtering. I've never owned one personally, but I rode with someone once for two hours who had one. 1.37, K Filter ON, TSF On, Highway. It got annoying pretty quickly. Granted, you can knock it down with Advanced mode and I did not experience that firsthand, but New England still has a good amount of real K band, particularly in Massachusetts, so I really need all the range I can get to combat the terrain we have. I can deal with my DFR6's K Band noise, but the actual range can get a little dicey sometimes.