Ultimately, it depends on the horsepower. I wouldn't say that it's more prone to failure then a manual transmission, its just the lack of an aftermarket for the automatic makes it difficult to build to withstand high horsepower. You wouldnt take a bone stock 5spd and hook it up to a 400-500hp turbo b series and expect it to last long either, however there are solutions for that, upgraded LSD's, gears, syncros, clutch, etc. The automatic has nothing, everything has to be done custom and from scratch, and often times its hard to find people who are credible and have the experience to do those modifications. I would say that if your planning to keep it under 300hp, an OEM rebuild, and a beefier TC would take you places for the time being, again the issue is the electronics. Im gonna go out on a limb and say your transmission is an SX4A. I appreciate the respect though really, im so jaded from constantly being shit talked just for owning an auto, regardless of the amount of legitimate work I put into it.