Theres got to be some way of pushing the 16v a little bit more.
From what i can tell the 1.6 is a pretty decent engine, shame its not on a moddable dizzy (MOARRR REVS)
Can spark plug gap distance effect performance?
Cooling air as best you can often can help so trying to keep engine heat away from the induction system is an ok place to start.
Direct cold air feed with no joints in the pipes should have a small gain.
Lightweight wheels i recon would help a tad.
Always stripping cars down works, but who would want to ruin our lovely fiats

!
Less restrictive mani/exhaust system,
Performance plugs, does the 1.6 have a knock sensor? maybe it could make use of higher octane fuel!
(Sorry to ressurect this thread, i'm just eager to find a way to push power a bit.)
I have a 1.6 sx marea you see

.