I do not think that going up from 172.5 to 175 if going to get rid of glowing headers.
Make sure jet needle is in the 4 groove down from the top of needle.
Like I said check your pilot jet size. 45 with 4 turns out. Turn out 5 1/2 if jet is a 40 or 42.5
Order a 45. Glowing should go away.
If your plug is clear or grey on end of plug then put in the 175.
If plug is grey to part black, then jetting is fine as is.

 

wouldnt u wanna change ur pilot jet before goin to 5 turns out, i thought it was like if u go past 3.5 or below 1.5 then ur pilot is off?
I know theres somethin def wrong wit my jetting, rode today wit a piped and jetter raptor and bone stock '03 predator, they ride together alot and they both said the rap beats the pred in a drag by 2-3 bike lengths, but today rap said he was jetted bad and the pred killed him, i raced them both and beat the rap but lost to the pred, i jumped him off the line w/ ease but he started passin me and on our top ends we leveled out, he was bought 2 feet ahead and stayed there. Wit a stage 1 i shouldnt have a prob against a stock machine, im ready to thro that carb out the window, in the year ive had it its not been jetted correct once, course changin of my exhausts and weather has been a factor, i just need to get a lot of jets and take the time and spend the day tuning it correct... prob take the whole day lol

 

The stock carb seems to have an effective range that it works best of 2 to 6 turns.
4 seems to be the mean. I agree in that it is better to change the jet than run at 5 1/2 turns.
It was only a suggestion to use if getting a new jet may take some time.
When you get too far out the spring in the jet does not have much tension and vibration could cause the pilot jet screw to fall out. This would be the case if you go beyond 6 turns.

 

I'm not familiar with the trinity pipe but think its a real close design to my CT pipe, I ran a 180 main, clip on bottom position at seal level and at night you could see my header pipe also kind of glow. I know that it wasn't running lean. Also I had a full Yosh pipe on my raptor and the header pipe would also glow at night & mostly at idle - the jetting was correct, I then called yoshimara and they told me this was normal. At first I also thought it was lean and messed around with the jetting and ended up basically chasing my tail. Give trinity a call and see what they say.