When I first bought my R3 about 9 years ago, I organized a group buy for the GIPro for members of this and another owners' site - about 100 takers all together.
What the fellas' here say is right on. ATRE is unnecessary for you due to later model year improvements from the factory and Tune ECU.
The gearing on our big girls will take some getting used to for some, so, if you count yourself among that group or if you are a gadget hound, Landstar, I'd recommend going with this unit, their newest model;
GIpro X-type G2 gear indicator by HealTech Electronics Ltd.