I already cut it...
Only paid $50 so I wouldn't worry too much... didn't feel like to paying $120 + shipping for that tiny pair of grip panels.
The aluminium grip panels are very tough and I ended up chopping it off w/ my metal chop saw.
As sfinney suggested, I cut it slightly oversized, then used the flat file to hand fit the grips.
Came out pretty good... now, I need a set of screws bad.
The old screws sticks out too much.
Thanks for your help guys~