Nissan Repair: 1991 300zx TT EFI harness replacement?, electronic fuel injection, 300zx tt

Question
I am the original owner of a 1991 Nissan 300zx twin turbo (73,300 miles, manual trans, new engine at 35,000 due to water inrush into engine).  I have an intermittent, very rough idle problem, and also a hard start problem.  Service dept. tells me that my EFI (electronic fuel injection) harness is corroded, causing poor connections and instructions from the computer to the injectors.  Service dept. also says that the engine must come out to replace the harness.  The job was quoted at between $3000-$3300.  On-line forum enthusiast posts indicate that some have done this repair  only by removing the plenum, or maybe some hoses.  Service says I have a leaking gasket, which it will fix all at one time when the engine is out.  

I'd like to keep the car if practical.  Would you fix if you were me, and is there any way to have  what needs to be done be less expensive?  Should I expect other major systems to fail on this car at this age?

Thanks in advance.  Regards, Shuki

Answer
Shuki,

Yes, I would keep the car and get it repaired.  I am sur the harness is corroded from the water previously and much of the harness is below the engine so it would be replaced from the firewall out.  I would do the whole thing at once.  You could check with a Nissan speciality shop to compare prices but only one that did Nissan cars for a living.