Was planning on ordering the newer plug n play harness GMS1, but I have read so many issues with the GMS1 I am wondering if I should even do it at all.

Anyone have issues with the newer harness, or were all the issues with the old crimp/solder harness?? I like the fact that its still all warrantied...

GMS1 - 290hp/315tq - How is milage effected from stock??

Trifecta = ??? How is the milage vs stock??

 

I got same milage with stg1 crappy, 21 I changed the intercooler and hot side and now get 25 to 27. Ask me next week about Trifecta I am just waiting on the mailman to bring the cable.

 

the plug and play harness should eliminate most of the gms1 issues. just make sure the lower sensor gets clipped and rotated like it is supposed to and you should be good if that is the route you would like to go.

don't know about the mileage


you may have had a slight boost leak if you picked up that kind of mileage from changing the ic and piping. 21 mpg is definitely low.

 

As the saying goes, "Don't fix it if it ain't broke". I happened to have an expert tech do my "airbag" crimps with the proper die and torch almost 2.5 years / 28k miles ago.

Still holding up just fine. Only if I encounter a problem will I change them to a prefab harness.

 

Trifecta might give me better mileage, way more low end torque, however it is way more fun to average 16 so far.