ECU Upgrade/Boost Questions

[gregsj@mail.imm.com]

Fellow Audians, prior to an ECU upgrade, the boost guage on my '91 200 
TQW would sometimes read 1.8, but easily read 1.7. After the upgrade 
it read 1.8 pretty quickly and stayed there. After a week, the highest 
reading I'm seeing now is 1.6. I had my mechanic check all of the 
usual hoses. He has a smoke generator as well which he sent through 
the system under pressure and found no leaks that way either. Where 
should we look next? TIA for your help and expertise. GregJ