I have it, It sounds alot different from an H-pipe. I was pleased with it. The hole for where the gases can cross over is kinda small. I haven't had any other o/r mid pipes, so I wouldn't know a power loss/gain. I got it just because nobody had it to just experiment.
I bought the same MAC off road X-pipe in May 2002 for $159 (looks exactly the same as the one listed in the website listed in the previous post). I installed it on my 93 GT with shorties and 2 chamber catback for a week. The fit was perfect. You can definitely feel that it pulled better in 4th gear than the H-pipe did. It was quieter on the inside (2K rpm drone was MUCH quieter-higher pitched-not as deep) and outside than the off road H-pipe I replaced. WOT from the outside was also much quieter. It may be louder outside on an LX since the tails go straight out. I personally prefer the sound of the H-pipe, so I swapped it back after a week. Right now the X-pipe is sitting in the original box beside my washer and dryer.