Bridging EAR 890's

I would take the extra money and put it towards cables, music, room treatments etc...

One thing I am curious about: Have you tried running these without the subs connected at all? How's the sound?

WHY? Honestly, your amp is 70 wpc of pure tubes, your speakers are 92db at 1 watt. That puts you at about 110db continuous. That's without a pair of 500 watt subs. Are you using a crossover on the speakers or running them full range?
By bridging to 140wpc will only gain you about 3db which probably isn't even audible.
I do speak from experience having owned the 509's with coincident speakers rated at 92db. Things got pretty loud at 10 watts. I can't imagine needing 140wpc.

Hey, everything is overpriced. Buy a clock radio...or be an audiophile.

Seriously though, I owned EAR 519's and they were really sweet. EAR has a unique personality which I found a little too "tubey" for me. I get a lot more detail out of other tube amps I have-just a personal choice though.

If money didn't matter, I don't think I would go back to EAR amps but if I was stuck with your amp I could live happily ever after and never look back :-)