[AKnowles]

OK, I hopped under the car again today and traced the hose. It goes from the heater supply to a feed just below the alternator. I beelive the original part number is 996-106-212-06 and the new part is 996-106-212-11. At least the hose looks correct. So, my completed parts list looks like:

1 900-123-144-30 Crush Washer/Sealing Ring for Coolant Drain Plug (10 X 14 X 1 mm), Boxster/Boxster S (1997-04)
1 996-106-222-17 Water Hose to Water Pump (3-Way Hose), Boxster/Boxster S w/Manual Trans. (1997-04) (Purple Arrow)
1 996-106-501-07 Water Hose to Water Flange at Oil Pump Housing (Large Hose), Boxster/Boxster S (1997-04) (Orange Arrow)
1 996-106-502-06 Water Hose to Water Flange (Large Hose), 986 Boxster/Boxster S (1997-04) (Green Arrow)
1 996-106-212-11 Water Hose
1 999-512-609-09 Hose Clamp 32 x 12
3 999-512-589-09 Hose Clamp 25 x 12
1 999-512-606-09 Hose Clamp 29 x 12
2 999-512-594-09 Hose Clamp 53 x 12
2 999-512-668-09 Hose Clamp 49 x 12

Maybe this'll help the next guy looking for parts to do the same job.