Go get a cowan if you're hurting that much for carbo DJ. Overrated af in my opinion. Steel is real etc.
I looked at getting a Cowan........then started doing more research about them.......fixed seatpost height was the killer for me......I like my seat slammed when racing and raised a bit when playing about on DJ's or at the skatepark.Jackal for the win on that one!
I know a couple of people who have ran it with 140 and had no issues but I wouldn't want to go any higher. I've seen people run the meta 4X with 169 upfront so could consider that?
I have ridden mine from 90mm up to 150mm.. I am happy with it at 120mm. The bike is already Slack, 150 made it too Slack for me.. But I actually ride big proper dirtjumps on it, so I can't go too Slack on it.
Edit... You were talking 4x.. I was talking about dj.. You will snap a Headtube off at 180 on the 4x.