There was a fair amount of blog reporting on GM's IPO papers, focusing on various outsized risks reported in those documents. But for someone who has read a fair number of red herrings in the past, I can tell you these over-the-top risk statements are virtually pro forma. The lawyers don't want any suits down the road about failure to disclose, so every risk up to and including getting kidnapped by evil trolls if you buy the offering are listed.
Via the Accounting Onion, I found an issues I have not seen well-reported. Tom Selling argues that without some accounting shennanigans at its reorganization, GM's equity should be negative. Reading between the lines, it does not appear that he is very confident that the SEC, which is a branch of GM's ownership group, will do much about it.