Ideally as close to the nozzle as practical, but in light of the relatively small volume of juice in the ID of 1/4" OD tubing, anywhere in the Engine Bay is fine. Leave a low loop to make the siphon effect less noticable.

Another question.
Should the pressure gauge take off between the pump discharge and the injection nozzle before or after the shut-off solenoid...or does it really matter :?:

I'd put the gauge between the solonoid and the nozzle so you can see a momentary drop when the valve opens. Gives you some positive feedback that the system is actually functional. Would also show if a line was disconnected or broken anywhere between the pump and nozzle.

After the shutoff solonoid. Let the gauge tell you you're delivering.

Chadow, you get my PM regarding this?

That sort of makes sense but when the valve is closed, won't it see vacuum and when it opens it will see pressure. There would also be more fluid to suck out and have to be refilled. Only if it'* before the solenoid, will it see a momentary drop.
It it is before the valve and the valve doesn't open, it would not know, so putting it after would make sense.
Since I am going to leave the gauge in the engine bay, I won't be able to monitor while driving anyway.

If you're not using it in the cabin, put it between the pump and solonoid. That way if the ignition is on, you can see under the hood that you're primed.

Yeah, I got it, just let me know!

Pump is mounted. Perfect fit.

Now there'* a tricky fit
Thats where my filter is, just above so there might be enough room?