I elected to install my HFS-3 system completely in the engine bay.
The pump can be seen behind the (relocated) driver's side horn, and is mounted to the bottom of the headlight tray (the headlight tray can be seen at the top of the picture, taken straight on the fromt driver's side). Yes, that is plumber's tape and zip ties, but it's in there nice and solid. I fashioned a steel mounting bracket in place of the provided bracket for the plumber's tape to wrap around without touching the pump surface itself.
Methanol is stored in the stock windshield washer reservoir (which is over 2 feet tall... perfect for gravity feed). I put a T (visible in lower right) in the line going from the second washer pump to the headlight sprayers.
I am going to inject directly after the throttle body. I purchased a throttle body adapter with NPT taps from USRT, seen here.
The relay and FAV are mounted with zip ties where an automatic transmission A4 would have it's ATF reservoir. This shot is taken top down, you can see the washer fluid reservoir in the lower left.
Wiring goes through grommet holes in the ECU box, then down the back into the cabin. I had to wire the red, blue, and yellow connections to the cabin, so I braided them lightly for easier routing. This picture was obviously taken without the ECU box cover on. Tapped wires (for RPM, Fuel injector, throttle position, etc) can be seen coming out of the ECU wiring harness.
Temporary placement of the control box and gauge while tweaking threshold/gain, etc. There is a nice cubby just below where the control box will be permanently stored.
