I'm assuming you mean using a brat kit. Hacking off the ass and installing a new tail section. It really all depends on what you do with it. The length of the shocks and whether or not you run a rear fender will be the things to consider. On brats like you're talking about most use fairly short shocks, somewhere in the 10.5 to 11" range. That will get the low stance you're likely after. If I'm right I'd suggest some stiff shocks otherwise if your running a rear fender you'll likely bottom it out often. Even with stiff shocks you still will, but stiffer shocks will help a bit. What's your plans?