I have a 908 that I love and have carried daily for about 2 years now. It's never had a single hiccup and eats everything like most 3rd gens. My question is since the 908 is billed as the more "economy model " of the fist cousin 3913, what should I consider to beef it up at all to make sure it stays stout? I know the guide rod is plastic vs steel. Are those interchangeable with steel ones? Are there other upgrades I should consider? Again it's never failed. I probably put 150 rounds a month through it. My other 3rd gens are 6906 and 4586TSW. Any advice would be appreciated!