Oooo, a test!
1- Overboost switch on intake manifold (1.1 bar, +/- 0.1 bar, I think)
2- Air recirculation valve on turbo (emission control - this can be disconnected)
3- Corrugated pipe between exhaust manifold and EGR valve (EGR valve can be disconnected too)
4- Transducer(s) for air recirc valve and/or EGR valve (these can be disconnected or removed)
5- Vacuum amplifier for transmission vacuum circuit
6- Overboost switchover valve (signal from #1, above)
7- Transmission switchover valve (I think)
8- ALDA (anneroid compensator)
I may have #6 and #7 backwards, can't tell from the photos without tracing the vacuum (or pressure) tubes. The smog junk can be disabled or removed if you don't have emissions tests in your area, you may get a slight increase in MPG and part-throttle power. If you want an explanation of what all these do that would be a MUCH longer post!
HTH,