235/65-15 or 275/75-15 are very good substitutes.
Replace the tire
Yes , you can replace a 205 50r 16 with a 205 60 r 216. You must replace in pairs, not a single tire.
The best idea to replace a tire which has a whole in it is to replace it with a new one. Reason as to why you should replace it because the tire can wear out and blow out sooner with a whole in it.
No, you typically cannot replace a spoke without removing the tire.
Yes you can
Generally requires removing and dismounting the tire, replace TPMS sensor, remount tire, balance tire, re-install tire to vehicle, do the relearn tire position procedure.
You can not replace just the tire pressure sensor on a Boxster. You will need to replace the whole sensor. The sensor is located inside the tire assembly.
Yes, you can.
Yes, it is possible.
Yes you can
Yes you can
It depends on the cause of the issue. If the tire is damaged or worn out, you may need to replace both the tire and the tube. If only the tube is punctured, you can just replace the tube.