The new one is actually steel, not aluminum. It started off as a Honda 400EX part. After cutting my old frame & comparing it to the Honda part, it was about 5 lbs heavier. After all modifications were completed, i'm about 7 lbs lighter than when I started. Keep in mind that I had already done away with the rear fender, fender supports, & grab bar. I was already using a lightweight aluminum grab bar previously, so the bike was already pretty light (for a zilla) to begin with.
The hardest challenge to overcome was getting the geometry of the brake peddle & stock rear master cylinder to work together since I had to relocate the peddle mount about .75" further down the frame tube. After notching, bending, re-welding, & lightening the peddle, I then shortened & re-threaded the master cylinder pushrod & made a new master cylinder mounting bracket.
Other modifications included cutting 2" off the front half of the exhaust tubing where it meets up inside the pipe and welding tabs to the frame to mount the new removable sub-frame. The main reason I did this was for better access to the back side of the motor / rear shock area. The added benefit was I saved a few lbs & I think it looks more unique.