Thanks for the thread start.
I can say from my personal experiance, that the Q3 can get you to the 1.26-1.25 range on a bone stock bike. They are that good, and I can't say enough good things about those tires. They've also been the so labled as the "Offical OTP Instructor bike tire" for the past two seasons.
Now to your points. The GPA Pro's are a full on race tire. They are a DOT standard, but I wouldn't recommend them at all for the steet. The sizes between all componds are only in the 190/60. I've yet to have install these tires onto any bike that they wouldn't fit. (Save for maybe adding a link to a chain to push the wheel base back.)
The GPA's come in a 190/55 (for 600's) and 190/60 (for 1000's) These are again a race tire, but are now a couple seasons behind the GPA Pro's. These tires, I'd be more than comfortable using on your street bike for a race and then to the street.
Last DOT's are the Q3. They come in almost any size you would want. 160's, 180's, 190's, 200's. As mentioned, I love these tires and use them on the Echo Cycle RSV4 Demo bike this season and the Honda Demo bike last season.
The slicks, 165, or 200's. (I don't bring in the 190 slicks. If wante they'd be a special order) The Medium Plus(8477), is the technically the hardest slick tire. Made mostly for durability and works well in all temperature ranges. It's essentially the do it all, Dunlop slick tire. As metioned above, due to its carcass stiffness, it does speak to the riders the most. Dirt riders love the tire, lets you know in very good detail to where the edge is, similar to ripping around in the dirt. Riders such as Mike Yurko or Ian Wall use this tire as their go too.
The Medium(7455) is in my opinion, is the tire you should be using at Castrol and most other tracks. The carcass is a touch softer, and the compound is softer still than the 8477. The issue thats been had with this tire is quite a a number of riders haven't set-up there suspension to suit the tire for the track. (As they came from Pirelli's the season before) Now this was also a huge issue the first year we rode at Castrol when I sold the Pirelli's as well. Once the suspension has been set-up (I recommend Vass Performance) I've had many people get great useage and life out of the tire. I was able to use the 7455 slick for 5 track days this spring in California and I'll use it again for round one's practice. Another note for the tire is, you have to use it with warmers. Goes without saying, but I've seen it more than I'd like. Lastly with the 7455 it is best used in at least +20c ambient temp and track temp of at least 35c. (If your ever wondering what the temps are, always feel free to come ask us at the Empire tents) This will be the tire that Justin Knapik, Jon Bullee, and many others will use this season.
Finally, we get to the Soft(2662) slick. The cat's ass. This would be the best performing tire that we offer. With that said, if the suspension isn't 100% dailed in, it will only last 15-25 laps. The lap record at Castrol is done with the 2662 tire. Jordan Szoke. (and I know I'll be tring out this tire more than once this year as well. Haha)
Now with all this said, there really isn't a bad tire out in the market anymore. You definitly do have your top two brands in the market, and in the end it comes to personal preference. I've sold both the top brands, and its hard to fault either one. Each have there pros and con's. Tires can become very personal, and some people (neither myself or Max) try to sell them as if the brand owes them something... The fact is, the tires you choose are the only piece of equipment between you and touching the ground in the wrong way. It's best to try things out and see what you like. Either way, I appreciate all sales that come through Empire Tyres.
If you need/ want anyother info, please feel free to text, call or come see me at the track.
~Scott