Due to what seems to be a weak/failing starter, I'm contemplating replacing mine.

Who makes good quality starters (better than Harley Davidson), maybe even a high performance one that will fit an 08 Road King?

 

the HD units are very hard to beat, especially fit and fininsh. I have tried all the different brands of aftermarket starter motors out there over the years and no one in particular has shown to be better in any measureable way. the chrome and polished stuff holds more heat than non. if your bike is stock or close, get the stock unit, or repair yours, the most common failure is the starter clutch and it is replaceable without replacing the whole motor.
just my 2 cents.
m

 

The starter is usually the last thing to cause starting problems, but people love to replace them.

How did you troubleshoot the issue?

 

Yup, what Dan says. I'd be looking at wiring connections grounds in particular before digging into hard parts.

 

Yes, I looked that up to see what could be the cause.

I did process of elimination so I put in a brand new battery and replaced both cables, the starter has got to be the only thing left...

 

Make sure those grounds are SOLID!!!!
Many issues from that that could be avoided.

 

Do the later models still have the big wire mesh ground strap underneath? Those were notorious for issues and getting missed in troubleshooting problems like this.

 

What exactly is the issue?

 

A clunking noise when you push the button, a sound like a ballpeen hammer hitting the primary.

I understand it's due to a design flaw the 07's and 08's have, a compensator issue, this is my reasoning for wanting to replace it with a good quality aftermarket starter instead of just another Harley starter...

 

Have you tried bumpstarting the bike? Have you looked in the primary? Have you pulled the starter out and tried testiung it? I've read before where a fellow bought a starter, didn't solve anything - finally opened the primary and the rotor had nuked the magnets and chunks were in the stator and preventing the motor from spinning.