Another Tip xD:
Getting 83+ is achievable if you bust your butts off, and get tutor (if your economy allows you too). Having said that, if your already disadvantaged in maths, say, you have a really bad foundation from yr 10 onwards due to whatever, and you find math methods somewhat, not copeable. Then I suggest back away. However, if you believe your foundations are strong, then do specialist.
If you do specialist, and you perform well , by means of getting a 35, be proud that you can hold your head up high when you say, i got a 35 in specialist
I endorse specialist, but, if your ATAR dream is something that is hard to reach, further maths is the safe route..you gotta look at your options, and whats the best way to get that score, given that we don't know whats your circumstances
Most of the guys here, are probably doing specialist knowing they are already awesome at mathematics in general and confident to take up a challenge.