After searching high and low, and buying some hallow rods as a mistake, I have finally found the best Sig Sauer replacement guide rod out there (P239 shown in pic)...
They are a little pricey (everything Bruce & Co do is, and worth it), but these are the closest one can get to the original SIGARMS solid carbon steel guide rod that should still be shipping with new guns. Beware of others that are duracoated--the finish will wear off with use.
The new polymer rods are a problem and such an idiotic place to try and save money! A solid steel replace guide rod is a must have for any new Sig (if you need a how-to, please buy a Glock instead).