Good luck, people have unkind things to say of the Gems system but having not experienced one I'll not comment - I have the Hotwire on my 3.9Ltr and have never had cause to plug it into anything and nor did I my previous Plus 8 with similar engine.
If it starts running rough I'll investigate where and how it needs to plug in, I think people worry unnecessarily when they start monitoring things they didn't know existed.
I do know that a new set of plugs and leads + rotor arm every now and again helps to keep things suent, the bottle of Forte fuel additive has certainly returned the snap to my 27 year old and improved mpg.
