Just received the controller today and have done a test fitting to ensure that it works. The control pad is actually pretty small about the size of a box of matches (see pic).
Generally the hardware looks well put together, the only thing I might question is some of the wiring harness connectors look look they need some strain relief fitted (the wiring pins could easily pull out of the molex-style connectors if the harness got caught on something). I will need to conjure up something with zip ties/tape/heatshrink before I properly install it into the car.
Very easy install. Unplug the accelerator pedal harness, plug one end of the ETC harness into the accelerator pedal and the other one into the factory harness (it's basically a piggyback). Other ETC harness plugs into factory OBD Port. It only uses 2 wires of the port, ground and constant 12V. When I install it properly I'm going to cut this connector off and hard wire the module into constant power so it frees up the OBD port.
Both ETC harnesses connect into the "main" module. Then the control module with LED display plugs into the "main" module. All are small enough to tuck under the dash trim.
On road:
I really need to hook up the reverse gear override. It is otherwise uncontrollable whilst reversing the car if using some of the higher "Sport" settings. The override consists of a single wire which needs to be 12V+ when reverse gear is engaged.
On Sport 7 (highest), 1st gear revs out very quickly with minimal throttle input. 2nd and 3rd gears also, I am quickly going over the speed limit without realising it. (Gotta retrain the right foot). Even in SP3 the throttle response is very good perhaps a bit more than I want.
After a few laps of the block I have settled on perhaps SP2 to be ideal for everyday driving, and up to SP5 or so for spirited driving where you have a clear run of road ahead. SP7 is pretty mad (literally) I wouldn't use this except on the track.
SP2 is very very nice and takes away the initial doughy throttle when accelerating from a standstill, in all forward gears except for 5th when the 2.5i starts to struggle anyway.
But yes, really need to hook up the reverse gear bypass if I am to use this module full time

The LED display shows not only the current mode, but when you are moving it displays a numerical indication of % throttle opening which can be useful in some situations. It is very bright at night though so you might want to mount it out of direct sight; I'm thinking either under the dimmer knob, or on the RHS of the centre console where it is blocked by the wiper stalk.
All in all, a good buy. Looking forward to getting it properly wired up and installed, then playing around with the settings more.
Note: 2 harnesses available for Libertys/Legacies. 2A and 1B, I believe the earlier MY04 and perhaps even MY05 need the 1B harness, whereas newer ones need the 2A. Easy way to tell is to look at your accelerator pedal harness. If it's about 2" long then it's the 1B. If it's about 1" long then it's the 2A. Unfortunately the advertising literature isn't too clear and the seller was good enough to send me both harnesses just in case