Kerry- I can help you. I have had the D&D and drilled out America pipes on my Speedmaster. The D&D flow the best. Current pipes are stock America pipes with all four baffles removed. Very close to the D&D. What you will find with better flowing pipes is a faster spin up of the motor and about 6-8 more hp at the rear tire, which is very noticable. When you do the exhaust, get an airpump removal kit so it doesn´t spit and backfire on deceleration. With the pipes will be a little lean unless you are at altitude, but it shouldn´t hurt anything. If you are mechanical, change your primaries up one step, assuming a sea level altitude. The D&D are loud and have a vintage blap sound. The hacked up Americas have a deep loud thump. Both are very cool and very different. Save you money and get a air box removal kit. Similar gains to the exhaust upgrade. My D&Ds are on ebay right now...