Not sure what you mean by wireless, just guessing you mean you have a wireless modem currently on ADSL broadband.
If so you won't see a lot of difference from my experience.
Your provider will supply you with a new wireless modem which you will have to set up and connect all your devices to again.
My experience is to stay away from the major suppliers.
We have been through a few and have lately been with Spintel and are now quite happy.
Lots of drop outs with TPG and Amaysim.
If you want good download speeds go for a plan 1 higher than their base, usually 50Mb, the standard plan is probably slower than your existing ADSL.
We have fibre to the box inside, but I have also used friends internet that is fibre to the node and really you wouldn't know the difference.
It would be different if you wanted really high speed, but for general use it's all of a muchness.
Cheers,