The only thing "Bose" in the truck is the amp. The speakers are still the same paper coned type junk as the non-Bose ones. Any aftermarket speaker should sound better.
As for the treble problem, make sure that there are only 2 wires going to the speaker. GM liked to bi-amp the speakers in the Monsoon systems. They used separate channels for the driver and tweeter. If there are 4 wires, then you grabbed the "midrange" channel instead of the "treble" channel. You have to get a set of speakers with exposed tweeter leads and cut them and wire them to the other channel, or bypass the amp.
It's been awhile since I installed a set of speakers in one of these trucks with Bose so I don't remember if they bi-amped or not.
I removed the earthquake speaker and replaced it with the bose speaker again. I realize that the "bose" crap that's in the truck from the factory is no good, but I don't think that the earthquake speakers do a major difference..
After checking around I found out that they are cheap and not really that good.
It was only 2 wires connected to the speakers so I don't think it is bi-amp?
I have found a focal utopia kit unused and for well under half the price of new, think I will buy it and put it in instead
I had a non-Bose system and did the same thing. Replaced the front speakers with aftermarket JL Audio components (6.5 mid and separate tweet). Sounded like crap with the factory unit power. Finally got the aftermarket amp in and wow what a difference that made. Aftermarket speakers sound 10 times better than factory but have to have enough power to push them. I'd recommend you ditch the factory stuff and go aftermarket. You will be much happier.
As I answered mpbond, the earthquake system isn't really that good.. Looks like it will be the focal utopia's for me!
My headunit is actually not stock, I forgot to mention but I replaced it with a pioneer AVIC F40BT last fall! Think I'll need an amp to power the front speakers in addition to the headunit