Not to hurt the boston name but the pro60's as well as the older Z6's are not even in the same leauge as the SR6500's. I have never once had a person walk into my shop and listen to both and tell me that the bostons were a better sounding set. That goes for the Focal K2p's as well. The polks are just so natural and sound even better when installed correctly in your car.
Now the crazy thing is. The SR5250's actually sound better than what the SR6500's sound. The midbass is pretty close to even on the 2 so dont throw that into the mix. The SR5250 just sounds alot warmer. They almost make you want to crawl up next to them and snuggle.