Stock tires were P. There is no reason to exceed what the factory thought was safe from frivolous lawsuits, except if you're going to be carrying heavy loads or towing big trailers which could benefit from the stiffer sidewalls common to the LT tires.

Load range D or (God forbid) E tires will turn your ride into a lumber wagon, as far as ride quality. Don't even think about it.

I hate Sam's Club and Costco when they act like they're doing me a favor to sell me tires. Often times I end up buying the tires and taking them out the door. Or mail ordering from Discount Tire.

Ask a question on this site and you will always get the more expensive answer. For example, build a 440 for your Newport cruiser and you'll hear, "You need a forged crank". Clearly you don't, but the majority will say you do. Buy pistons for that same motor and you will hear, "Have to have forged pistons, hypereutectic aren't good enough." Rework old heads for your 4000 mile-per-year cruiser and you'll hear, "Put in hardened seats" even though it'll hardly ever see full throttle acceleration more than 5% of the time.

The tendency is to err on the cautious side, especially when they're spending somebody else's money!

R.