Everything sounds good to me, larger brushless motors are pretty loud generally speaking. Especially with a lot of metal drivetrain components.
As far as gearing, no one can accurately tell you what is safe to run as there's tons of variables such as weather, driving conditions, driving styles, wheels/tires, batteries, etc. Back in the day, I would use a temp gun and run the car on a particularly hot day as I would normally run it and check the temps on the motor and ESC periodically. Assuming nothing has changed in the last 10 years, 150-160 degrees Fahrenheit is a pretty safe temperature to run normally. If you're running cooler than that, then you can gear up. Anything over 160 degrees and you start to run into the possibility of electronic failures and you should gear down until you reach that safe operating range if you want to run it like that for an entire pack.
Two ways you can change the gearing. Pinion and Spur, both accomplish the same thing, but changing one tooth on the pinion will have a much more dramatic effect on the power output as well as heat output than if you were to change multiple teeth on your spur. 9 times out of 10, you can get away with just changing the pinion and I would always keep a few of varying tooth count on hand so I could really dial my temps in. If I remember correctly, each tooth on my pinion would change the motor temps +/- 10-12 degrees depending on whether I would go up or down on a tooth. But as mentioned earlier, that's heavily dependent on all those variables so your experience may vary. It's best to experiment and find what works for your application.
If you really want to avoid wheelies, the best way IMO is to run 4s and you'll get a little more wiggle room to gear up without running too hot and be able to limit some torque and get some of the speed back that you lost from not running 6s. Smaller tires help too, since there's less rotating mass, but depending on where you plan to drive, that may be out of the question lol. The 2.0 also has a center differential, lightening up the fluid in there will help put some of the power to the front wheels and limit what is sent to the rear. I believe factory is 20 million weight oil. Dropping it to 50-100k should help quite a bit if you still want to run 6s. I would get a pack of differential oils of different weights and see which one you like best because just like gearing, there's lots of variable at play.
Suspension wise, if you look on YouTube, I believe UltimateRC has some old videos on suspension tuning that are super helpful and in depth.
