Sorry for your damage!

 

Damn first i ever heard of that happening on an IS. Try and find a used one from a junkyard or something though, if your doing labor yourself, it will be much more cost effective.

 

I've tried to stay within the diameter on my old setup but got a set of 19" G35 Rays, the two rear tires were different profiles, 35 and 40, didn't know how i missed that, but thats over an inch difference, could it be the cause?

 

Could be cant run 19s with 40 series it threw it way off. But here a link to a salvage awd hit them up
http://cgi.ebay.com/ebaymotors/06-07...#ht_1013wt_722

 

^^^already did thanks, $350 isnt a bad deal, was hoping the damage wasn't so bad, was planning on keeping the car but I guess it wasn't meant to be....

well i just removed the Differential, that thing looks like a mess on the inside, definitely wasn't repairable

 

Wow busted pinion. Make sure the replacement has the same gear ratio. 250s and 350s might not be the same.

 

Im almost postive thats what happened. When i was running experimental tire sizes, the vibrations just felt un-natural. So i knew i had to change back to the usual sizes right away. Fortunately nothing happened to my differential, as far as i know. I know i ran those experimental tire sizes longer then i should have too, but so far its ok.

 

You are correct, I'm so used to how most RWD vehicles use bolts. Those pop out like on a Honda.

 

It's most likely your staggered wheels causing the problem.