I'm in agreement with DaveP on this one. Having installed a bunch of 4105's (Avital and Viper) over the years, white smoke is something I've never encountered. I really doubt you got two bad units. You are correct in that the 1995 Imprezza is very straight forward to add a R/S to, no bypass module and only 3 ignition wires. Power locks are a bit of a chore.
Rather than buying a few dozen 4105 controllers, perhaps a very thorough review of the actual wiring would be the best course of action right now. Below is a text of the 4105 harnesses. If you fill that in, the forum members might be able to see an issue and save you further cost in parts and possible damage to your car.
Viper 4105 -------------------------------------------> 1995 Imprezza
Main 9 Pin
1 LIGHT GREEN/BLACK (-) FACTORY ALARM DISARM
2 GREEN/WHITE (-) FACTORY REARM
3 YELLOW (+) IGNITION OUT (TO ALARM)
4 WHITE/BLUE (-) ACTIVATION INPUT
5 ORANGE (-) GROUND WHEN LOCKED
6 BROWN (-) HORN OUTPUT
7 RED/WHITE (-) TRUNK RELEASE OUTPUT
8 BLACK GROUND
9 WHITE (+/-) LIGHT FLASH
R/S 5 Pin
1 BLACK/WHITE (-) NEUTRAL SAFETY SWITCH INPUT
2 VIOLET/WHITE (AC) TACHOMETER INPUT WIRE
3 BROWN (+) BRAKE SWITCH SHUTDOWN WIRE
4 GRAY (-) HOOD PINSWITCH SHUTDOWN WIRE
5 BLUE/WHITE (-) 200mA 2ND STATUS/REAR DEFOGGER OUTPUT
4-pin satellite harness diagram
1 BLUE (-) STATUS OUTPUT
2 ORANGE (-) ACCESSORY OUTPUT
3 PURPLE (-) STARTER OUTPUT
4 PINK (-) IGNITION OUTPUT
Heavy gauge 6 Pin
1 RED (+) (30A) HIGH CURRENT 12V INPUT
2 PINK/WHITE (+) PROGRAMMABLE OUTPUT FOR ACCESSORY OR IGNITION
3 RED (+) (30A) HIGH CURRENT 12 INPUT
4 ORANGE (+) (30 AMP) OUTPUT TO ACCESSORY CIRCUIT
5 PURPLE (+) (30 AMP) OUTPUT TO STARTER CIRCUIT
6 PINK (+) (30 AMP) OUTPUT TO IGNITION CIRCUIT
Door lock harness, 3-pin connector
1 BLUE (-) UNLOCK OUTPUT
2 EMPTY NOT USED
3 GREEN (-) LOCK OUTPUT
Soldering is fun!