Which is correct?
or
I see it both ways fairly often.
It’s entirely up to Lance Turbo’s Kickass Conglomerate. It’s their name and, when they are registering it, they can put in a comma or leave it out, as they prefer.
However, when Lance Turbo’s is being written about in the press, if the writer is using the AP Style Guide, he or she will remove all the commas before “Inc.” The Chicago Style Manual recommends the same thing.
If, on the other hand, the writer has the good manners to recognise that the choice of name is a matter for the corporation and not for him or her, he or she will respect the choice which the corporation has made and not substitute his own choice or that of the author of some style guide. 
Style and punctuation are not a matter of “good manners.” They are a matter of style and punctuation rules. If your house stylebook says remove the commas, then remove the commas.
Corporations’ marketing decisions with regard to their names need not be considered when it comes to monkeying with things like puncutation and capitalization.
Note that many corporations themselves do not follow the form in their official corporate papers. When is the last time you saw a store whose sign read “J. C. Penney Co., Inc.”? They would have it as JCPenney, which is itself silly.
Well, technically the style book covers issues that are not covered by the hard-and-fast rules (or rulings that differ from those rules). Style and rules are two different beasts. If one chooses to ignore Chicago (which is okay), then one must go by one’s own style guide.
While it is a matter for debate whether a style guide should trump the corporate person’s choice of name (I think it should not), the AP style guide does indeed recommend eliding the comma in corporation names.
–Cliffy