The '03 and '04 RX-1 Mountains use an earlier design skid, I think it's the Pro-Action, and it's heavy, around 82 pounds. A pretty common move is to swap it with an M7 skid, you can pick them up used for $400 or so, they have a better angle of attack and are 25-30 lbs lighter. I just did that swap last week.
Now, if you only ride in the mountains a couple times a year, and want a good trail ride, you could do a lot worse than the standard RX-1 skid, especially if the price is right. What kind of price are you seeing on it, and is the 151 track available? And will you be keeping that skid in for riding in your local area, or swapping your short track back in? I also wonder what's different between the Attack suspension and the RX-1 one-it may be just longer rails, in which case a rail extension kit would get you by.
BTW, I think I found the one you saw at TY-$150? Can't go too far wrong at that point, especially if you have a track available. With any luck it's a bolt in, not sure if the mounting points are the same on your Attack.
OK, so really not much help here...I tried!
Brian
