Wonder Chips - add 35 horse

[Solomon Ngan <sngan@netaccess.on.ca>]

I have a '90 90Q20V, non-turbo, rated @ 164hp.  Someone told me there is 
a chip (chips) that I can buy (cost around $400,$500) that would increase 
the 20V output by around 35hp.  He told me it wouldn't hurt the engine.  
Someone has installed something similar in a new VW Corrado.  It serves 
up a noticeable performance.

Has anyone installed one or know of them ?  Any precaution ?  Oil cooler, 
etc ? 

But what I don't understand is that, for a atmospherically run 
engine, how could you increase engine output just by changing a chip ?
I heard of changing cams or exhaust, or equipping it with turbo, which 
actually change the mechanical performance of the engine.  But how could 
a chip do that ?  Too good to be true ??

Solomon Ngan     '90 90Q20V / '84 5000S