I've seen a bunch of fragmented discussions on this but want opinions on lower-cost systems that have the best sound without cutting down on power. The ones of seen that are not way up there in $ are the RM Carbon Fiber system, a K&N cone filter, and the Dali Monster filter. These are all reasonably priced. I took off the engine cover which adds a little to the sound, but want to add more to the sound without having to purchase a new exhaust system. Opinions, anyone?