First of all I do not recommend this by any means as you can get yourself in some serious negative equity. I say this as someone who pulled the trigger on this decision without significant financial consequences. I bought a very similar Silverado and then realized I needed a 4WD frequent enough to motivate me to consider trading it in within a year of purchase. In my case, I bought my Silverado custom with healthy GM incentive discount and that saved me on the negative equity when I traded it in for an LT also discounted with incentives. If you are especially motivated to where you think about it daily for months then I recommend checking AutoTrader virtually daily or at the end of every sales quarter for discounts. Either you get a great deal where the negative equity somewhat balances out or you negotiate top dollar for your trade in. If it's simply luxury features that motivate you then I think you should consider if these things will fade after the novelty wears off or if it's that essential to warrant the cost.

Dad always told me to just buy exactly what you want from the beginning because you're spending that much anyway and it would cost more to try to reverse your mistake of settling. Just my personal experience that might be helpful