I'm getting ready to do a top end on my 06 CRF250r. I want to change out the valves to stainless steel but have a few questions. 1. It's my understanding the exhaust valves are already stainless from the factory, so it seems fair to say that I just need to replace the intakes? and just recut the exhaust to freshen them. 2. What brand, other than Kibble and White, are top quality valves. 3. Can I use my factory springs, etc? Thanks!