I'm sure the 156 parts are the same as the GT parts but you'd be best to check with Ebspares first, they may also have braided hoses - they are a very helpful company
Brake hoses are messy to change and do take time. You also need to take care not to get brake fluid on any paintwork, if you are not happy to do it then it may be best to leave them as they are. This is a brief description of what you would need to be do to change them on a 156 if I remember correctly - dont know if the GT is much different.
There is a fixed connection with the steel brake line fixed inside the wheel arch behind the suspension strut. This has I think a 17mm nut on the hose side and I think a 13mm nut on the fixed pipe side (sizes could be 13mm and 10mm – cant remember). Also the connection is fixed into the bracket by a spring clip, which when you remove the spring clip the connection is loose from the bracket.
First you want to unhook the hose from the upright, there should be a rubber grommet over the hose and this fits into a clip on the upright. Next go back to the fixed hose connection between the hose and the metal pipe and remove the spring clip. Give a good clean with a stiff brush to remove any mud etc, use the spanners to loosen the connection slightly. Next I would go to the caliper and loosen the hose connection to the caliper. Go back to the fixed hose connection and completely unscrew the connection - there will be some fluid loss so be prepared for this. I would put a piece of tape over the metal pipe to stop some of the fluid coming out and rags to sock it up.
I have heard that putting cling film over the top of the brake fluid reservoir can reduce the amount of brake fluid that comes out.
With the hose loose you can now unscrew it from the caliper. Next you will need to remove the rubber grommet from the existing hose as probably the new braided hose will not have them and fit to the new hose.
Now you should be able to refit everything in the same order.
I use one of those pressurised brake bleeding kits and its pretty straight forward to use without any problems on the 156.