The Toto UltraMax #MS854114S is the best available in every way and should be within your budget if you shop carefully but is worth whatever you have to pay for it.

The Kohler toilets are very handsome but the flushing mechanisms are the same as the Fluidmaster units you see in hardware stores. In my experience, they either continue running or won't fill forcing you to leave the top off the toilet so it is easier to fix it and having to turn it off when you leave for more than a day. I've never remodeled a house where the Kohler toilets (even really nice ones) didn't go into the dumpster. If you buy one go to Kohler's website where they explain with photos how to remove and clear the top of the mechanism when it jambs so you only have to take the top off the tank once every other month instead of every week.

I also have Toto UltraMax toilets, and they are great. They are generally above your price target however. You can go for the Toto Drake, which is also very good and within your budget. For pedestal sinks, I used Duravit, Happy-D model. They have quite a range of pedestal sinks, but may be outside your budget. They are very nice however.

The Ultra Max and the Drake are both bargains for what they are. The Ultra Max is an elegant one-piece toilet with a modern tank shape and the Drake is not but they both have the G-Max flushing system.

I second the motion on the toto ultra max, I purchased one about a year ago...best toilet ever!! It'll never clog, you can throw away your plunger. I think if you shop around, you can get it for around $350, but remember that this price includes the silent close toilet seat, which some toilets may not include in their price. Also, I like the fact that it's one-piece, because it makes it easy to clean in the space where typical two-piece toilets would connect together, between the bowl and tank. Find a way to get this into the budget, you'll be glad you did!

On YouTube there are many toilet videos especially of the Toto Drake and UltraMax. You can see how well they work and also get a better idea of what they look like.

Here is a link that might be useful: Toto videos

You might search the Plumbing forum...lots of strong opinions there about toilets!
I considered Toto, but the price with 3 bathrooms in the new house seemed excessive. Ultimately, I chose American Standard Cadet 3, which I've been happy with so far. It got good ratings on the MaP testing. We did find a defect in the glazing on one bowl, however, but our plumber exchanged it for another with no problem or added cost.

Here is a link that might be useful: Maximum Performance Testing for toilets

We have the Kohler Cimarron toilets which have the "Class Five" flushing system which is similar to toto's flushing systme and they have been great. I believe that Kohler is now using the Class Five system on other styles too. We also have the large Kohler Memoirs pedestal sinks and have been very happy with them. The large Memoirs pedestal sinks cost more than $350, but it comes in 3 sizes and the smallest one might be around $350.

The Kohler Cimarron Class Five toilet has a reputation for providing inadequate bowl washing. Kohler's Class Six version adds that feature. I don't know why they would even offer the Class Five system; no one wants to brush their toilet bowl more often.

The Kohler Class Five system is their basic system and is in no way similar to Toto's G-Max system.

The Cimarron seat height is objectionable to many ambulatory homeowners.

You can see all of these toilets on YouTube videos.

Here is a link that might be useful: Kohler Class Five video

Here is the Kohler Cimarron Class Six system.

Here is a link that might be useful: Class Six

Here is the Toto Ultra MAX II 1.28 gallon video.

Here is a link that might be useful: Ultra Max II

Here is the Toto Drake test. You can see why it isn't important to pass more than a 700 or 800 gram test unless you plan to use the toilet for something other than human sanitation. Bowl cleaning, noise, and speed then become the important issues.

Here is a link that might be useful: Toto Drake test

Kohler recently stopped making the Cimarron with the Class 5 system and now only makes it with the Class 6 system due to consumer complaints although some may still be available from dealer stock.

TerryLove.com is one of the best sources of information about toilets. There are 4 pages of homeowner reviews since 2006.

Here is his opinion on Class 4 - 7 systems from the Cimarron review forum:

"The problem with the Cimarron is mainly the trapway, which has not improved since it was introduced.
Class 4,5,6,7 are marketing terms now. The numbers mean nothing.
In real use, a Toto class 4 is equal to a Eljer class 7.
A Eljer class 7 and Toto 4 are better then the Kohler class 5 and 6.
All of these use a 3" or larger flush valve. But you still have to look at the trapway. That is where the clogging occurs.
The Cimarron trapway has too tight of bends where it leaves the bowl. It does clog more then other trapways out there in real use.
If you look at quality of construction, and consistent rinse, then the Toto class 4 comes out at the top.
Toto doesn't keep changing the number, they are the ones being chased.
4 was meant to be a classification for commercial products.
That's as high as you get.
The other manufacturers can come out with
Newer, bigger, ... it doesn't change a thing.
My personal experience with Class 6 Cimarron, is that the rinse is now 360, but still not very good."

Here is a link that might be useful: Kohler Cimarron reviews

We have a Cimarron class 5 and a Toto. I prefer the Cimarron in terms of flushing (the Toto is prettier, if you can call a toilet "pretty"). DO NOT get a Kohler Memoirs toilet. We are considering replacing the toilet and pedestal in the half bath because tha toilet is so awful. I actually prefer the taller height of the Cimarron, but we are tall, I can see that it would be an issue for someone more petite.

I have to agree that the Kohler Memoirs toilet is one of the worst ever made. I have one that has probably cost me many thousands of dollars in water and repair bills over 20 years as well as new flooring (if I had the courage to add it up). It is so difficult to admit you made a mistake and to replace what appears to be a first class toilet. If someone stole it in the middle of the night I would be elated. Could this be related to the Stockholm Syndrome?