I just finished my Carrera fuel line replacement job on my 85M491.
Although my lines appeared good and after removal still appeared to be good, after all they were 29 years old.
First, get your hoses from BoxsterGT, Len.
I attempted to do the job in situ but was thwarted by the little bolt that holds the line to the fuel pressure regulator. I just could not get a socket on it. It was too hidden by fuel line and wire harness.
I then went with the take off the right side manifold technique first. That was very easy. I then saw the condition of the fuel injectors and made the decision to do a full R&R of the fuel injection system.
I took the left manifold off and disassembled all the components. Cleaned and cleaned.
I went with alternative fuel injectors from a Jaguar, see
http://forums.pelicanparts.com/porsche-911-technical-forum/327832-alternative-fuel-injectors-14.html. $120 for all six, free shipping and got them in two days.
I changed the o ring under the throttle body, cleaned and tested the AFM, cleaned and tested the ICV, checked all vacuum lines and replaced a few. I also changed the fuel pressure regulator and fuel damper and thermo switch on the throttle body, throttle console bushings and return springs because I was in there. Also, I did the triangle of death, oil pressure switch and breather gasket.
Now my thoughts.
If you decide to change out your fuel lines take the entire fuel injection system and R&R it. There are old parts and pieces that should be changed based on age alone.
My car has never started from a cold start better, no hunting and no rich smell!! The engine sounds better, more "even". Acceleration is very smooth and linear, no flat spot or bogging.
This job was definatly worth doing. I was a little stressed when I realized that my entire FI system was dismantled and sitting on my bench. But my son put me back on track when he said, "just put it back one component at a time, and you always have the support of the Pelican BBS".
The hardest part of the job was removing the intake gaskets from the heads. About half of the gaskets on all the ports were welded on. I sprayed gasket dissolving spray every day and slowly got all the gasket off. I did not remove the shroud but worked under it by lifting it with one hand and scrapping with the other.
I do not think that removing the engine would have made the job much easier, but removing the shroud in total would have been better.
About half the intake nuts were loose when I went to remove them. I used thick Belleville washers to prevent this in the future. McMaster has 8mm washers that fit perfectly.
Don't procrastinate, do this project for peace of mind if nothing else.