So, after Boss bought their 300M hardened input shaft for piece of mind on his trans and having issues with it, I decided to give it a go because my converter like his, is also a Precision Industries unit. I figured maybe he was having issues because of his being an older unit. So, it wouldn't fit the transmission that Level 10 built for him, neither would it his Precision Industries converter, but barely fit his OEM converter. So I bought it thinking as before, maybe it was just him. As soon as I received it, I noticed right away that the splines were made way differently than the oem ones. As long as the dimensions are correct, it will fit. Tried to get it into my converter and no dice. It would start a little bit and that's it. It would be in a bad bind. I even went as far as bluing it with layout ink to see where exactly was it making contact. It's basically metal to metal about 1/8" on up. If you were to somehow get it to go in by force, it would never come out without destroying either the transmission or converter. So, I started looking at it under magnification. The oem splines are like axle shaft splines. They resemble a gear tooth in that it has a triangular shape that is slightly rounded on the sides. This gives it strength and no sharp edges. The Level 10 shaft was machined with what appears to be a ball nosed end mill or a round radius hobbing cutter. The top is flat, not pointed slightly and the bottom is rounded, not a smooth V-shaped like the oem. So it would never fit in an oem shaped/sized female splined hole in the physical universe we occupy. At least, not without reworking the whole thing. That negates the whole point of buying a machined part and having to re-machine it just to get it to fit. So, I brought this to Level 10's attention and explained what was wrong. They said that it takes them upwards an hr of work to get their shaft to fit a PI converter, as if PI makes theirs to the wrong spec. So I called PI and they verified that they manufacture their female splines to the exact specs as oem and that if it doesn't fit, then the shaft is wrong. So I went and tried to get it in my transmission. Same result, would start a little and immediately get in a bind. So the shaft is junk. Will not fit by any means. I was even told to try sticking it in the freezer for an hr or so and then try getting it in the converter. Anyone who knows anything about a contact fit like that, once it's in, it's never coming out. So that would have ruined my $1170 PI converter. I explained again that it would not fit neither my converter, transmission or Boss's. They said give them 24hrs to resolve it. Well, it's now Tuesday and their resolution is tough ****, deal with it. They do not have any return policy on "race" parts. They manufacture a junk part and do not support the end user if it's defective. It would be different if it were installed and somehow were broken, well no ****. I race with it and break it, my bad. But when the damn thing doesn't even fit to begin with, there's a problem. I do not recommend Level 10 for any type of transmission work/repair if they're not going to stand behind a product they sell that is one of the more expensive ones. I ordered another shaft from PATC and it wound up being a TCI unit. But guess what? It fit like a glove, both converter and trans. You know why? Because it was manufactured properly. I will not ever recommend Level 10 to anyone because of their piss poor customer service and selling someone a bad product and not standing by it.