I've had the 990 and 7125 for almost a year.
I've used them with B&W DM603 Font, CC6S2 Center, and DS6 Surround.
I'm going to be replacing my DM603 speakers with the 804S this week.
Because of this, I'm wondering if the 125W is going to be good enough for the 804S speakers, or I might need to go up to 200W.

Thoughts?

They're both rated as 90dB efficient. I'd give the 7125 a good try before worrying about it. If you really feel that the 7125's being pushed too hard, you could also consider a pair of M2200's, but I wouldn't take that step until you'd given the 7125 a good shot at it.

I'd give the 7125 a good 2 months before (maybe) going from the 7125 to the 7700/7500.
I am also planing to replace my center with the HTM4S, but its only 88dB sen.

That's the difference between the output power of the 7125 and the 7700/7500: 2 db, the same as the sensitivity difference between the speakers you mention.

My suspicion is that the 7125 will still have you covered. Give it a whirl and let us know what you think.

The 804S speakers should be delivered today.
I'll try it out with the 7125 for a few weeks and see how it sounds.
Later this summer I'll get the center speaker.

Well, this is going to take longer than I hoped.
The 2 speakers got delivered by FedEX ground today.
When I opened them up, the tweeters are broken off the top of the speakers.
I spoke to the guy I bought them from off of eBay, and you can see in his pictures that the speakers were not damaged prior to shipping.
Now he and I will have to deal with FedEX claims to get this resolved.

Ouch! Shipping big, heavy stuff like that can be such a pain sometimes. I hope you guys can get some satisfactory resolution.

It’s always a very good idea to have images just before shipping and during packing process.

I bought a used Sunfire Signature sub once. I pleaded with the seller to take images of the sub next to the unpacked double box showing all sides of the sub plus more images: the insides of the two empty boxes showing packing materials, with the sub packed inside the boxes before sealing, and the final, ready-to-go package. How very fortunate he did.

The box arrived apparently undamaged, but when I picked up the package, something was ‘clunking’ inside. Apparently the box fell off a shelf in a truck or of a truck onto the pavement, landing squarely on one side therefore leaving no dented corners or tears. When I opened the box, the 1” braced MDF side with the active driver had cracked away inward on two corners and along 1 1/2 sides. The magnet structure had broken away from the driver’s frame and was free to roll around inside the sub’s cabinet. The built in amplifier circuit boards had been smashed by the freed 25+ lb. magnet.

When I called FedEx, their over-the-phone response was, “Not our fault. It was either shipped damaged before shipment or improperly packed by the shipper, therefore the refund or repair is up to the shipper.” That’s when I sternly brought up the fact that we had about six images showing the condition of the item and how it was packed. I was asked to take the package to a FedEx location for inspection. At the FedEx facility, they merely said they would send a report to the claims department.

When I called the claims department again after two days, they said the box wasn’t damaged on the outside, so it couldn’t have been their fault. The shipper took over at this point. He sent an email with the six images he had taken attached, plus six more I took of the damaged sub, and filed a written claim. The twelve images were near infallible proof that the sub had been shipped in excellent condition and boxed properly in the original factory boxes with original Styrofoam and corner spacers, then was damaged by a force that caused the thick cabinetry to break inward. FedEx finally accepted responsibility when the images showed that my estimation of what had happened was almost certainly what did happen.

My advice: always, always, always ask the shipper to take a generous number of images of anything in used condition that can be broken in shipment.

That's excellent advise. I went through something similar when UPS mortally wounded my old Model 750 when I shipped it out back in January. UPS wasn't as resistant to admitting blame, but it may have been because I went to the UPS Store that I shipped it from with pictures of before and after and an e-mail from Scott describing the repairs that would be needed to insure that it worked reliably. That did uncover one other interesting lesson, though: unless you insure the package for its value and the cost of shipping it, they won't refund your shipping fee just because they broke it while it was in their possession. I ate a pretty decent shipping fee on that one.