System upgrade advice

I doubt you will outclass those electronics with those 804's, but I would audition them first. If you can find a dealer to loan them to you, that would be best.

I like the Paradigm Studio series, but can see where some can find the tweeters subjectively "hot". Speakers should be where you spend the most time/money getting your system to sound the way you think it should.

"I'm considering replacing them with maybe some used speakers around $2.5k (pair) like some B&W 804s."

You'll make the problem worse doing that. Also, you're not going to solve the problem by just going out and buying something new. The whole system contributes to the problem you are having. You need to have some type of plan or goal as to where you need to end up, or you'll spend a lot of money and not fix anything.

Looking at your system, I suspect the problem may be shared between the tweeter in your speakers and you preamp. But just remember, anyone who hasn't listened to your system first hand, is guessing. You can start by connecting your CD player directly to your amp and use the volume control that Oppo gives you. Play some CD's that are giving you the most problems, and see if things get better, or worse. That will give you an idea as to what you need to do.

I agree with those that say the B&W's will be as bright as your current Paradigms. Maybe brighter.

Whats steps have you taken with your current speakers to reduce the shrillness? Have you experimented with room placement relative to your listening position? What about the room itself? Do you have a lot of hard, reflective surfaces in your room contributing to the high end harshness? If so, start to balance the room out with soft, sound absorbing materials - heavy drapes, area rugs, etc. More often than not, the room is the overlooked component in a system.

Finally, your Paradigms have metal tweeters and so do the B&W's. They simply may not be offering a sound that is right for you. If you resort to new speakers, audition some with soft dome, textile tweeters. You may find their sound smoother and less harsh. I know I do. Good luck solving your problem.

I used to have Paradigm Studio 80s and liked them, especially for the price paid. However, my current Gallo Reference 3.1s and Reference AVs are far superior in all respects.

The Gallo CDT tweeter is a thing of beauty and one of the best I've ever heard. In addition, the dispersion characteristics are far superior to the Paradigms. The sweet spot with the Gallos is enormous - you can sit to the left of the left speaker and still clearly hear the right speaker.

I have also heard similar comments about the GoldenEar Triton speakers. And most of them have a built-in subwoofer and digital amp that provides a very satisfying bottom end.

The Paradigms are very good, but there are better speakers out there for the money...

I agree with others that say B&W is not the answer. Look at speakers from Dynaudio, ProAc, Sonus Faber, Vienna Acoustics, Soliloquy, etc.
Speakers that have a soft dome or silk tweeter will usually sound a bit more relaxing than those with metal dome tweeters.