Before changing all the high priced parts, check out the relays. I know from experience that the same manufacturer makes the LR relays as Porsche relays, and I had an identical problem on my porsche that was a relay that went open circuit when it got hot. Symptoms were the car would not restart for 5 - 60 minutes, then started fine.
Local Porsche dealer ordered the relay from Germany for a 1981 car! and got it in 2 days by fedex, and it cost me only the part ( $15.95) which was cheaper than all the USaftermarket parts sources!
Not sure where you live, but if its a high ambient temp area, think vapor lock as well.
Neil