apparently the slope mod doesn't come without a price... I need something that does the same thing for pipes... i searched pipe mod but nothing relevant... so is there anything like the slope mod but for pipes?
And why do you need such a mod? You aren't always playing the game in "underground view", are you? ::)
I have to agree with io_bg here. I'm not sure why you would need a pipe mod, but you have a couple options.
You seem to be suggesting that you're having problems with pipes since you installed a slope mod. You can remove the slope mod temporarily, do whatever you need to do with the pipes, then put it back. I frequently have to remove my slope mod to build bridges, for example. There's no harm in doing this.
Another option would be to eliminate the need for those pesky pipes altogether. You can install a mod to increase the power and water radius, so you don't have to micromanage power lines and pipes. Some people see this as a cheat, but I think of it as one less thing for a busy mayor to do. You can find the mod HERE: RalphaelNinja's UtilityRadius TrafPollution Modd (http://www.simtropolis.com/stex/details.cfm?id=21352)
I believe the Underground Depth Mod v1.0 (http://www.simtropolis.com/stex/details.cfm?id=21366) by Thalassicus is what you want. It lets you place pipes at just about any slope.