He's right, but then the nightmares start. Updated kernel modules, finding the kernel, finding the kernel source. If you don't understand any of this you are in for a learning curve. Any wise computer professional will suggest the least path of resistance and the lesser of the evils. Updating your kernel is not for a newbie.
Reproduction of your customer's install is going to be extremely hard since any package can be installed which may modify any number of potential parameters and cause imprecise results.
Linux isn't easy for the beginner and debugging complex issues where you have to reproduce an environment will be a complex task.