It's easy to see what the benefits of going AWD are - Better launches, less torque steer, traction in general to help power through corners on the track...

Has anyone experienced any negative effect from going AWD? Other ways it changed the characteristics of the car, or how you have to work on it, changes you had to make to wheels/suspension/brakes, etc. Maybe things that don't get talked about as often, anything from either a street driving, track driving, or even a maintenance perspective.

I feel like part of the novelty to these old Japanese rice rockets is the FWD drivetrain, but from the outside looking in AWD looks like an all around improvement, not just for drag racing. I'm mostly interested in how much AWD may improve handling on one of these cars, versus a FWD Honda that's fully outfitted with an equally upgraded suspension/drivetrain.

 

Decrease in MPG from the added drag and weight.

Increase in NVH especially if great care is not given to drive line alignment. Still more rotating parts so more NVH.

Depending on application, smaller fuel tank.

 

The only negative impacts I could see like the OP said, is more rotating parts which has a potential of breaking. From a performance perspective I don't think there are any negatives.