I have a wr400 and I am going to turn orange. Is the p-38 modification for carbs worthwhile for the 520. And what about the needle ocebn (or something like that!). Holes on air box have been discussed (from search) but it does not appear to have a cencensus about that. What are the standard well known modification on that bike to get more power, keeping the stock exhaust. Is the standard air filter good or it should be replaced by a k&n?