Verified answer

No one builds better trucks than GM. They are known for their reliability and longevity, especially the V8's.

If anything goes wrong, it won't be anything special that wouldn't happen to any other vehicle of that age with that many miles. You might blow a headgasket sooner or later, but that's a relatively easy fix.

Just make sure you keep up the maintenance.

And if you do put a new radio in and it dies, just pull it out and put it in your next vehicle.

My sister was only able to kill a GM truck by running it in Illinois winters with very low oil. But even then with 2 dead cylinders, I was able to drive it from Chicago to Riverside, CA with no problems.

8 years old with 300K. Someone has been driving a little bit in that one. Radio Shmadio, Put it in because it can always be removed. Go have fun, blow out your eardrums and win some radio competitions.

Put it in. The GM's are built like a rock. You should easily make 400k if they are primarily highway miles. Anyways if its a bust, you can take the system out...

That's alot of miles alright! If it was well cared for and maintenance done as it should have it might be worth keeping. But do not be surprised when something does go wrong!