I'm glad to see that you got it going using the OEM head unit , I'm sitting back looking at all the posts so far. About 2 months ago I went and had the pros look at mine and diagnose what makes it tick, I have been wanting to do something similar to Jimmytee, but using the OEM head unit. I had been searching prior to that for gold wing upgraded- amped systems and really nothing out there. Did a lot of research on auto OEM intergration and figured maybe it would work on this motorcycle. The results on diagnostics were similar to autos for equalization and roll offs but with a lot of distortion - off the scale with the factory amp and with the pre amp much better but still roll offs. Also different with motorcycle off and also with motorcycle running. They know that I'm doing my own system and gave me some guidance on what to do to achieve a flat or close to flat I should say OEM intergration. I going more toward a OEM intergration that is simple that analyzes to signal and corrects equalization from the preamp to the added amplifier. I'm hoping to keep it simple and on a lower budget, now seeing what you have done and got great results. I want have the fine tune tweaking that you have, but hope it works with adjustments on the amp, bass and treble settings - also will be adding a subwoofer to the system. Now to pull the trigger and hope it works as planned. I will do a post when I get it done with results- etc.