but i was wondering if its possible to cut the heat pipe so i can keep the stock mosfet heat sink?
This is not very possible, sorry.
Heatpipes are actually pipes, they're filled with low pressure fluid that evaporates and takes heat with it from one end of the pipe to the other, if you cut it that'll escape and make the heatpipe pretty useless.
Although you may be able to take off the heatpipe(s) and just use the mosfet heatsink, assuming they can come off but cutting the heatpipe really doesn't seem like a good idea, to me. Probably better to just get an aftermarket mosfet heatsink.
You could try taking the whole thing off as one piece, clean up the old thermal compound and put some fresh Arctic Cooling MX-2 or Arctic Silver 5 to see if that makes much difference but as you said the heatsink is hot, that must mean that heat is being transferred to it so I wouldn't expect amazing results. The sensor could well be faulty or badly placed, if the heatsink is hot enough to be uncomfortable to touch, that means it's over 50 degrees C (I think) and surely the chip is hotter than the heatsink because that's the bit producing the heat.
Are you overclocking the system? If not, you have problems but if you are overclocking it you might be a bit too high for the stock cooling to handle, try reducing the chipset voltage or returning to stock speed and see if it's still hot.
