Unless your Jetta can generate more G force onroad than my
install can, OFFROAD... I think you're going to be OK.
I cracked my windshield on a HUGE 25ft jump and the
mk2a never missed a beat.
As to heat, fans or thermal transfer via the casing might help,
but the secret in a later A2/A3/A4 jetta is to ventilate the dash
itself. Use a PC case fan and cut SMALL slits in the bottom
of it. Works good to keep those CDs from melting.
heh
Time for some fun in the snow
Ed
-Mk2a 10g @ Subaru WRX Rally car