@Mooh as mentioned, I spent some time listening to the side before deciding on the location of the port...keeping in mind arm position and direction of sound.
I was fortunate with the design of this instrument....laminate sides so no bracing to avoid or modify.
If you are considering and sides are one piece, general consensus suggests bracing around the area prior to cutting the port to avoid cracking.
Sound out front is not affected too much , on mine it decreased the low mid resonance slightly and actually cleaned up the A and D strings.
The port does make a big difference , like having a mini monitor facing you.
I used a dremel,sealed with a semi gel ca...crazy glue type product with a spray accelerator.
One application to seal, sanded with 600...blacked out with magic marker and another sealer of ca...600 to 1500 wet and polished.
Biggest challenge was trying to keep the hole concentric.