I have a 99 'stique....there is a greyish sensor on that side of the intake, it's the intake temperature sensor. Mine plugs in just fine with my cone filter(S+B) so I wouldn't worry too much about it fitting with aftermarket intakes.
Kyle
1999 Mystique LS (V-6)MTX Silver Heavily Modded
Happiness isn't about getting what you want,
It's about wanting what you have!