I have done same in my other car (not Porsche) from Yellow Hat in Times square center, and i must say they have good range to choose from and professional electrician to install at same time in car parking. Charges were ok too for installation, not bomb expensive like Porsche dealer.
Jump start the car and remove the jumper cable and see if car keep running its battery and if car stops after few seconds or minutes then alternator.
After first test if battery is weak then let it run for 30 mins and then switch off and start. It might recharge the battery and car get start. If you drive car less than 20 mins a drive eventually battery dies as battery complete one charging cycle in 20 mins.
It could be, or else he must have got that tire used one to put same km as other 3. i have done that once when one of my tire has death wobble due to swelling.
Check all fuses and relay and see if some are gone bad, change it.
Or else it need qualified mechanic to diagnose the problem like ARM
http://www.armotors.ae/index_new.htm
It sounds like accidental vehicle and then repaired outside with non qualified guys.
Better show to Porsche and let them diagnose once fully and fix seat belt issue too, as you never know if SRS sensor have been replaced after the accident or not.
i am a owner of Porsche boxter and i wanted to knw if there are good garages in dubai as i was in abudhabi and that is where i use to get the servicing done.
thanks
rgds