I didn't bother to read all the posts, but OP has three options:
1. get a lawyer. Just about any traffic lawyer in Austin will do, you've most likely received several letters from traffic lawyers by now offering their services. You'll probably pay the price of the ticket, but they have a high likelyhood of getting it dismissed.
2. Show for your arraignment and set the matter for trial. Hell, go balls and set it for a jury trial. This is Texas, you have a constitutional right to a jury trial in any criminal matter, including speeding tickets. Understand that you'll be responsible for costs of court, though. Once that is done, move the court to reset the trial date (this is a very common traffic attorney strategy). Next, show for the reset trial and hope and pray that the cop doesn't show. Without the cop, the ticket will be dropped. There is a chance the officer won't show for the original date either, your call, but keep in mind that in most police departments the officers get overtime for court appearances. so there is a decent chance he'll be there. By resetting you hope to get a trial date that is not the officer's normal court day in which case the odds of him showing are much less. If he does show, try the case and pay or plead guilty.
3. pay the ticket.
there you go. pick one and be happy.
'07 E90 335i ZSP, ZPP, Nav, ipod