It is an option for someone who does not want to get involved in the tuning process of his car.
So is a chip.
I researched the retrofit about 3 to 4 years ago and IMHO nothing has changed since then except more options have become available that makes the retrofit an option that just doesn't stack up with the other options available for tuning our cars.
The main thing that keeps the pcm retrofit around IMHO is the internet myth that the A9L pcm is the almighty gift from above and the 94-95 pcm's suck.
Things change....since the late 1990's I've seen stuff on these sites like....
Don't go higher than 355's or you'll turn too much rpm's on the highway
Forced induction can't be made reliable enough for a street car combo
65mm tb's are plenty for a street car
LT's are only for race cars
Since the crash, I think enough of these kind of threads about the A9L retrofit have been done to make me feel justified in sending the noobies to the search button who ask about this subject