Re: My GTV2.0TS just drank 2.0l of Oil!
I used to drive my Spider exactly the same way, day in day out for 8 months all over Europe. It used oil, but never as much as you describe (approx. 1L of oil every 1500 miles.)
The TS is known for using oil, but tbh yours sounds somewhat excessive. Running it empty is also a bit of problem as the bottom end may have been starved of oil, which I believe can come back to bite you on the bum a couple of months later.
As a side point, all those hard miles took their toll on my car too - it practically fell to pieces and cost over £6k in repairs!
-1998 916 Spider 2.0TS Lusso-
H&S Corse stage 1.
CATCAMs stage 1 cams with Savali custom ECU remap.
305mm discs with 166 4-pot callipers.
Ragazzon exhaust mid section.
Biscione Racing 2x70mm rear section.
17" Zender Siena wheels with 3mm rear spacers.
etc etc etc!