in 2001 I wanted some nice wheels, I was driving an 89 Cadillac that was reliable enough but a deer had taken it toll on the looks of the front end including sending a hoof through the condenser, I had always liked the 80 series since they were new and started looking at them on line, at the time they were going in the mid 20's, disgusted with the high price and "only a 6 cylinder" they did not seam like a value. saw I could get a
brand new Silverado 2500HD with a monster 8.1L V8 a stout Allison 5sp auto, leather power and all the goodies etc for just a few thousand more, 0% interest how could I go wrong buying new? I had never had a new car before, or not even oen built in the same decade I owned it, it seamed the right way to go.
Well that was my first and most expensive automotive blunder.
a few days after I bought it with 250 miles it developed a knock on cold start, brought it to the dealer who immediately went on the defensive, giving me a hard time making me drop it off several times trying to get me to just go away, they finally told me that it was normal condition and refused to look at it anymore

called Chevrolet cooperate and got nowhere, I was pissed, I should have called a layer and lemon lawed it right there. But I didn’t, I took the path of least resistance and just drove it

, talked to some other Chevy owners both in person and online all said it was "normal".

.
Only 2.5 years later with 65K on the clock it was going through a sumps worth of oil (8quarts) between oil changes and was starting to knock even when warm.
Turns out Chevy went to a very short piston with no skirt on the vortecs, this reduces the reciprocating mass of the piston improving fuel mileage, power and most importantly their CAFE #'s, if the bores of the cylinders were the least bit off the piston would tilt and rock in the bore wearing both the piston and bore. It is more prominent when cold as the piston it at its smallest.
PistonSlap.com
Plugs, forget the mileage on them but was probably around 30K
Some parts of that truck were great, they just botched some important parts, general build quality is not their either, If I had bought the "expensive" 80 series then I would be $20K ahead right now
Most likely your experience with the Sub will not be as bad, It might even just need normal maintenance (they get it right sometimes) you could also get burned on an 80 that has had poor maintenance,
but on average you are much better off with a Toyota than a Chevy, spend the time to find a good one in good shape with lockers.