I don't think that "trick" you did with making the PCM think it'* 35* out will work for long at all. The computer will realize that the value can't be correct and will use info from other sensors to compensate.
Also, not sure if this would apply to your model year too, but this is from a 2000.
This was posted by Rogue in a thread on IAT Tricking:
I doubt you'll see any timing advance even if your car is OBD1
As far as other mods go... if not done already, you really need a heatshield to protect your intake from hot engine bay air. It couldn't be good to suck in 150* air and tell your computer it'* 35*.
You may want to consider getting a 180* thermostat also.