My Neu Maxx is almost done

[Patrick]

Yes, the ofna 51t is Mod1 and is the only spur that I know of that fits the strobe without mods.

Were you getting 1/8th diffs soon? If you are I'd get a 20t pinion, because that will make it a tiny bit faster than 52/17 with maxx diffs. Maybe 21t.
If your not getting 1/8th diffs then a 18t should be good, maybe a 19t. 51/20 with maxx diffs is geared up a fair bit. I can use that with good temps on my 1515 2.5d (1700kv) and 5s. Should be doing basically the same rpm as your 1y (2200kv) on 4s (so same speed also), but I don't know how much lower my temps would be, because of the higher voltage. 51/20 does work ok on my car though.