All I seem to hear on here is tires, tires, tires.
The chassis is just a piece of steel.
If you can't make any of them work, especially something from a manufacture that should be at least close, it's tires, setup, something stupid someone did, engine or driver(for some on here it's even having the wrong driver, with the right ratio).
It's never the chassis unless it's bent.
When's the last time you read on here, about a brand of chassis keeping someone from winning?
Answer: never.
IMHO, if your not doing so good and you buy a new chassis and do better, it's not about the new chassis being better, it's about you buying something you ain't messed with yet, maybe even followed manufactures instructions with, and ain't messed up yet.