lower vs. higher grade suspension parts

[72truckster]

Im thinking of getting ball joints, Control arm shaft assembly and tie rods from Napa. Their seems to be a lower grade component rated at about 20 000km and then a higher grade with a limited lifetime rating. Im not really interested in the km rating as much as, the quality vs price difference. Basically don't want to overpay for something which would be overkill. The truck is stock and don't drive it hard or that often.

So what would you buy, the lower grade or more expensive higher grade?

Also would the Classic Parts suspension components be similar to Napa lower grade, the price seems to indicate so?

Thanks.