Fuel System

What began as a 1971 911T now has a 993 turbo engine and G-50 transmission.  The installation was done by someone who had never worked on Porsches.  Please don't ask.  Okay, my son commissioned the work as a surprise for me, and picked the wrong guy.  It appears the installer constructed a fuel line that runs from the tunnel exit directly to the fuel rail on the right side, using an AN fitting for the inlet connection at the rail.  Picture attached.  The fuel system has suddenly developed a leak at that fitting.  Both the fuel rail threads and AN fitting appear to be okay.  Can you suggest

Model: 930, Year:1987, Mileage:67K, Type of use:Street use only
In regards to wide open throttle WOR what is meant by do not approach anything higher than 12 - 12.3 AFR.What does the acronym AFR mean?

Model: Twin Turbo, Year:1997, Mileage:7300, Type of use:Street use only

Model: 911 turbo, Year:1977, Mileage:46000, Type of use:Both Street & Track
I have a 77 930 with origional turbocharger. Starting to see some smoke while on the turbo. Wanted to rebuild or replace seals while I have turbo on the bench for exhaust replacment. Have been told to upgrade to K27 but I do not intend to add intercooler. Current origional still makes plenty of boost. Should I upgrade?

Vehicle Information: Year: 1984; Engine (Size, Modifications): 3.3; Total Mileage: 37,000;

Vehicle Information: Year: 2003; Engine (Size, Modifications): stock 996 twin turbo; Total Mileage: 8000;

are you aware of fuel pump hose failures on 996 twin turbos/GT2s? (rupture of the hose from the pump, so the fuel just recirculates into the fuel tank with none going to the engine)

Vehicle Information: Year: 2001; Engine (Size, Modifications): 3.6; Total Mileage: 11,000;

lately the 2001 996tt fails to start. it cranks but wont start. it also studders at low rpms esp with start in first gear. cold starts are perfect.

Vehicle Information: Year: 1982; Engine (Size, Modifications): 3.3; Total Mileage: 149,000 km;

I have recently noticed that if I give the accellerator pedal a quick rev from idle there is a pronounced click noise that appears to come from below the throttle body. I had it looked at quick by an experienced mechanic. He felt it had to do with a worn rubber o-ring at the bottom of the trottle body and that the click noise was a metal to metal noise when opened quickly. Do you agree? If so is it a difficult fix? I am mechanically inclined but have little 930 experience.

Vehicle Information: Year: 1979; Engine (Size, Modifications): 3.3; Total Mileage: 94,000;

Vehicle Information: Year: 1979; Engine (Size, Modifications): 3.3 Turbo; Total Mileage: 95,000;

Can you fax me the specs for the fuel system? I have a new rebuild that runs great till it warms up,. I have checked the ignition at warm-up, it is working good ,which leaves me to the fuel system.....Thank You ....Rick