After 3000ish miles on HPR I'm sad to report that I found a fuel leak on my OM603. It was leaking from the suction side connection to the lift pump. I replaced these hoses a couple of years ago after I bought the car. The hose wasn't visibly damaged but I had the wrong type of hose clamp on there for the job and it was over tightened. I cut off about an inch of hose and reconnected. I'm not sure HPR causes leaks as much as it finds the any weak points in your fuel system. This fuel leak would explain why my low fuel light came on at just 550 miles, about 100 miles short of my normal range.
BTW whats the correct fuel line diameter? I have 5/16" hose but I suspect I should be using 1/4".