Yeah, Redcat dunerunner.
The engine is a chinese knockoff of a 2 bolt CY engine.
Yeah, they have rings.
The engine is very slow as it comes, but a tuned pipe makes it...uh...less slow. The tuned pipes available don't just bolt on though. They have to be modified.
You can mod the heck out of these engines and get decent speed from them, but you have to spend the time, and have the ability to do so.
The trans gears are very cheap plastic, won't last one day of running fast, and should be upgraded to steel, which you can buy for extra $, of course. But the problem with the steel gears is, they can generate enormous amounts of heat.
The electronics (TX, RX, servos) are horrible and must be replaced immediately.
The plastic is bulky enough, but a bit on the brittle side, so a wide front bumper comes in handy.
Dogbone pins shear off and come loose a lot....I could go on and on...

Bottom line is, you can spending a good chunk of time and money to get this particular model up to acceptable levels of performance. If you like to tinker, then go for it.