Im currently building the cruiser version of both Hasegawa kits, and I am not at all impressed with the TV SDF-1 .. its REALLY off. So many things from the movie version left as is instead of accurate to the show.
I don't think just the cannons would help. The 'Chest boosters' seem way too big, the Legs have all the DYRL kibble on them that wasn't in the show, the cannons don't have the rounded out notch, and the way they attach to the body behind them is completely different from the TV version.
Hasegawa is usually so good, i don't know why they did this.
If I could I'd return this kit to Hasegawa. Probably not getting the storm attacker. it looks like they still used a bunch of DYRL parts