Passat mods void warranty?

["Rokas Reipa" <vytas@erols.com>]

Hi. My dad is now looking around for a 1999 Passat GLS wagon. He is aware of
of the 1.8t engine and the modification potential it has and knows of
various chip upgrades out on the market. However, he wants to know whether
putting in an aftermarket chip will void the warranty. He is afraid he'll
have to wait for warranty to expire before he can push it to "at least
240hp", as he puts it. What's the truth?

Rokas Reipa
86 5kcst