Will upgrading my 100A fuse to a 150A fuse damage my amp?
A bigger fuse doesn't give more power. What it does do is raise the over load current rating causing more damage if the fuse needs to blow.
With two 35 amp fuses on the amp, the main fuse really needs to be 80 amps, not 100 amps.
Will upgrading my 100A fuse to a 150A fuse damage my amp?
Never use a larger-than-recommended fuse; if there's a problem with your amp, the larger fuse will allow more current to come through, frying the unit...