Just a couple of explanations...
Option 1 - Guilty plea with payment out of court. You'll get the total payable, demerit points, and likely a good insurance increase.
Option 2 - Plead guilty with an explanation. You will appear before a Justice of the Peace, and explain why you were going 81 in a 50. You may get a reduced fine, but that's entirely at the discretion of the Justice of the Peace. You will get the same demerit points, and likely a good insurance increase.
Option 3 - Not Guilty with a Trial. You will get a trial scheduled. Possible outcomes of that:
1. You fight it all the way, get convicted of the original offence. Same outcome as option 1 (maybe a slightly bigger fine), but it takes a lot longer to end up on your record.
2. You fight it all the way and win at trial. Charge dismissed. $0 fine, 0 demerit points, no insurance increase. (This doesn't include time/money you'd spend fighting it.) Just as a caution: Speeding tickets are very difficult to contest and most "wins" are actually technicalities.
3. The officer doesn't show up for trial. Charge withdrawn.
4. The Prosecutor fails to provide proper disclosure, you file a motion to stay the charge, JP (Justice of the Peace) grants it. Charge dismissed. (JP would usually just order an adjournment so the disclosure could be provided to you.)
5. It takes too long for it to go to trial, you file an 11B motion, and the charge gets stayed. (We're talking 1 year+).
6. You plead guilty to a lesser speed, like 15 over. Reduced fine, 0 demerit points, possible insurance increase (depends on your provider).
It's your decision as to what you want to do with it. FYI - "disclosure" is where you obtain the Prosecutor's evidence against you prior to trial, including the officer's notes and the radar/laser manual.
Hope this helps getting you started...