I didn't use the remote display, no, the flashing LEDs were plently, I had mine in the passenger footwell , just dangling by the wires so I could monitor whilst driving, but tuck it out of site when I was carrying a passenger, eventually it stayed hidden.
Using the VIP100 I found a 10% improvement in MPG, better running through the rev range, especially high up, and generally a smoother V8, I don't run LPG on my V8 any more, due to needing the space, and not doing the mileage I was, but as I say, it has moved to two other vehicles and on both it has made a dramatic improvement, on a V8 90 it took it from 8MPG to 11.5, though I did MegaJolt it at the same time with table switching
I reckon my VIP100 paid for itself within 2 months, I ran it for 12 months then gave it to a mate, as I went Megasquirt and wanted my boot back
The lambda sensor I was referring to was the one I run for Megasquirt, but the LPG one took plenty of wading too, and that is on it's third truck now! It was supplied with the VIP100, so dont remember what make it is, the one I use currently is a Bosch one, I think I grabbed it from ebay when someone had a job lot of VW ones going for £25 or so, since then I have used Fuelparts sensors also with no issue, on other trucks.