Well, first of all let me throw in a little disclaimer here… I am in no way, shape, or form an expert on drag racing! However, I do know a little about the fundamentals involved in, and the rules of thumb associated with, drag racing in general.
For instance, you probably know this already, but I’ll tell you anyways. If you were able to cut a tenth of a second off of your 60’ time that should translate into two tenths of a second in your ET. That said, the more power you can effectively put to the ground while coming off of the line, the better your 60’ times will be. However, since you already have a very good 60’ time, trying to improve upon it will not be an easy task by any means.
Additionally, I suspect that your LS1 (with forced induction power adder) already gives you substantial traction problems coming off of the line. With this in mind, I’m not sure how much having more power off of the line will benefit you. However, if you could boost off the line and manage to get traction then I would think that a 10.99 ET is right around the corner.
Try contacting Angel Robles (“angel” on surpaforums.com) from Florida… I know that he’s got a two-step in his T78 Supra and he seems to know quite a bit about drag racing! I’ll vouch for his skills too because I got lined up next to him for my very first run at Las Vegas 2001 (my first time ever at the track too). It was very ugly!

I ran a 14.1 to his 10.x, but I attribute the 10 cars he had on me as I passed the 60’ marker to his two-step!
Good luck with that 10.99 ET!