Keep or renew front roller blinds!

Then you have already given the answer about the price yourself. Someone has to install the windows after all. It will hardly get any cheaper. The company of course has to work cleanly. Unfortunately, you can't know that in advance, unless you know satisfied customers. I would keep the roller shutters. If the white tracks bother you, you can still paint them in the installed state.

If we want to replace the front shutters later, are there any disadvantages?

Are wooden windows coming back??? I would never paint wooden windows dark for durability reasons.