Is it worth upgrading a Thorens TD125

I Have a Thorens TD 125 TT with an SME 3009 tonearm.
I would like to upgrade it.It is in very good condition.
I would like an excellent midrange, very good base and very good treble.

How do I start?
I am not mechanically minded, so I will have to get someone to do the modifications for me.

Where do I start?
And what will I need?

Tks in advance for your assistance
.