Hey folks, I recently picked up this bike and am it using it for the occasional F40 race and trackdays. Some of you were extremely helpful last month in aiding me to troubleshoot the source of a few metal shavings in the oil (tranny dogs). I'm onto a new project and was hoping you might share some wisdom from your experience. I have read on a few threads here that this bike is prone to suffering valve train failures that often result from the spring retainers breaking. This thread, in particular, was insightful: http://forums.13x.com/index.php?threads/when-should-you-replace-08-gsxr-suzuki-valves.275868/ With all this in mind, I bought a spare complete cylinder head and was planning to rebuild it with APE titanium retainers and Yosh keepers. For cost reasons, I obviously don't want to replace the valves if I don't have to, so would inspect and measure everything and keep what appears to be in spec (valves and springs). However, I am planning on having the bike properly tuned by a fellow who also builds engines. In speaking to him, he advised me NOT to use the Yoshimura collets with the used valves because the original keepers have likely "worn into" the valves. So, specifically, I'm basically looking for a second opinion on whether to install the new keepers on the old valves, and more generically, am I on the right track with what I'm trying to do? Am I overthinking all this? The bike has 12,500 miles with a fairly unknown track history. Compression is 180-185 across all cylinders and valve clearances were in spec. As always, I appreciate any input. Thanks.