temp gauge.

Hey guys. Would like some input here. I ordered a temperature guage and adapter on Amazon. Its a 26mm adapter. Just a question where I put that adapter. On which hose is the best? I have a 2006 apex GT

I don't really like the stock orange color, I was thinking about putting in blue LEDs. Is there any direct replacement LED bulbs that will fit? Is there anything else to look out for when swapping them out?