what I've learned: - most of the time bone stock is the most durable - but - lifters, valve springs, main & rod bearings, seals, parts like that - use the highest quality parts you can find - often stock is best part - but not always.. s&s sells really good quality parts. gearing is more important than a hopped up engine. tires are more important than anything.
Nice to see someone else say it! I have made similar comments on here several times and I usually get slammed. Seems like most folks on here believe the aftermarket knows their bike better than the folks that engineered and built it. I grew up in my family's Buick / GMC dealership. I have always preached the value of OEM Parts. I will admit some rare cases where AM may be the right way to go but as a rule of thumb use OE when you can...