You should have no problems. I have a IC-706MKIIG, IC-2100h, and a HTX-252 in my 95. I run 100watts from 50MHZ to 20watts at 445MHZ. Depending on my mood, I may run 2, two meter rigs at the same time. One for voice, and one for APRS. Both at high power(I live in a valley) If I use my 5 watt HT inside the car, it sometimes has an effect on my tachometer and speedometer. That'* only if I am monkeying around with the radio. Hi Hi!
I do believe I have seen a picture somewhere, (unknown manufacturer) that showed a car inside a building with all the beam antenna'* pointed at it. Caption was somewhere along the lines of they test everything including throwing huge amounts of RF at the car while it is running. This was to (test) the capabilities of the PCM, radio etc.
1997 Pontiac Bonneville SEi-SCRAPYARD
2000 Chevrolet Blazer LT 4X4 4.3L
2002 Chevrolet *-10 LS Ext Cab 4X4 5.7 V8