I would not call myself an expert in this field, but I have had tons of experience with both types of motors. In fact, the same basic motor design of type I (84-87 Vette, 84-86 Fiero, 82-87 Firebird) then type II (88-96 Vette, 87-88 Fiero, 88-92 Firebird) are in the same family. The internal guts are identical, with minor changes to the housing and pivot arm.
The Type I motors are more mechanical in nature and require several relays to make them operate. The type II design (two wire as you call them) use a single control module that does it all.
I have had great luck with the type I in my 85 and 86 Vettes. They are noisy and slower, but the mechanical stress if far less than in the Fiero and they last a long time.
They are hard to trouble shoot, as it is difficult to determine if the motor or relay failed.
If you are concerned about your budget, I would suggest you take a trip to the local bone yard and try to get a handful of type I motors from Fiero and Firebird. This is after you verify if you problem is only a worn out gear. How do you do that? Take the actuator off and open it up. You will have to drill out the rivets, but no worries as you can replace with bolts. You will see the plastic gear chewed up, and or the center rubber pivot cushion will be mush. If so, just order a new set of gears from any Corvette retailer. Check out the Portal above, and you will find a source. Or, go ahead and experiment on one or two of the Fiero/Firebird type I actuators you picked up in the bone yard. This will get your feet wet cheap, and you will also may score a good set of brushes, etc, if you have to replace the internal electronics.
So, If the problem is electric (worn brushes, etc), the handfull of scrap yard actuators will come into play.
Here is a tip if you want to do the two wire conversion.
First, just go to GM and buy the complete right and left hand actuators with the brackets attached. Then, go back to the scrap yard and yank a Fiero type II or Firebird type II control module and all the pig tails at each end (you should be able to get one for two or three dollars vs. $150 at G.M. for a new one).
All you do is:
connect 12+ all the time power to the two red wires to the module
connect the black to ground
connect the white wire to the down signal from your switch
connect the yellow to the headlight on wire
run the two two wire jumpers to the actuators,
and................you have done it.
Or, just poney up the bucks and buy the conversion kit.
