It had an absolutely awful drone at exactly 3k rpms. The worst drone I have ever experienced. The drone was evident in every gear, as soon as you approached 3k it was there. Then if you passed it, it would go away and be fine.
Aside from that, I despise slip fit exhausts. You'll never convince...
Weird. I have the TSP downpipe, with their studs, and the blankets for turbo and downpipe, and I didn't have any of the issues you are describing. No modifications needed and no washers needed.
For sale is my PRL Titanium Inlet from my FL5. It has less than 300 miles on it. Includes brand new unused titanium studs as well. Not a single thing wrong with it. Just swapped to a larger carbon fiber inlet.
Price is shipped in the lower 48 states.
There's a whole thread on the Hondata forums where people struggle with the xdi 2000's and getting them to run correctly. I'm sure it's possible, but it's not going to be a simple experience like the 1530 or 1400
Id say if e85 is ultimately your goal, you are going to want the Full Race HPFP, Hondata 1530cc injectors, and the DW300C LPFP. Along with a CanFlex of course to read the ethanol levels. If you only did a LPFP, it would do practically nothing for you.