While normally a reasonable choice, your complaints about salt air and aluminum are a problem for this panel, as it has busses made from tinned aluminum. The bad news is that you have a Square D HomeLine panel. The bad news: you might want to rethink your choice of panel For your panel (Square D HomeLine), the correct kit is a HOML2225 this includes both the subfeed lug block itself and a neutral chair lug that adapts your fat 1/0 neutral to the panel's busses. The easiest way to do this is to use a subfeed lug kit to tap the busses on your panel. The good news: the parts you need aren't that bad As a result of that, and the fact that a 2/0 copper wire is rated for 175A (a standard breaker size) at 75☌, you're stuck upsizing this feeder to 3/0 copper hots and a 1/0 neutral, or chasing down a 175A circuit breaker for your panel if you can't enlarge the feeder wires. Since this is a garage you're feeding and not a house, you can't use the '83% rule' (aka Table 310.12 in the current Code), as that rerate only applies to feeders or services serving entire dwelling units. UL Listed file E8741.You need 3/0 not 2/0 for running this in copper Rotate enclosure and trim 180 degrees for bottom feed. Electrostatic powder coat, baked urethane painted. Includes combination sur face/flush cover. Listed for use as service equipment with twin neutral doubling as neutral/ground remove bonding strap for separate neutral/ground bars for sub-feed applications. Unused ne utral connections may be used for termination of equipment grounds. Main breaker type CSR at 35,000 AIC when used with CH or CHP branch breakers. Single phase, 3 wire, factory bonded split neutral, 42 (3/4') spaces, 42 poles, 120/240 volt. Rotate enclosure and trim 180 deg for bottom feed. Includes combination surface/flush cover. Unused neutral connections may be used for termination of equipment grounds. Single phase, 3-wire, factory bonded split neutral, 42 (3/4 in) spaces, 42 poles, 120/240 V.

Single phase, 3 wire, factory bonded split neutral, 42 ( 3/4 inches ) spaces, 42 poles, 120/240 volt. Main breaker loadcenters ch type - residential top/bottom feed - indoor nema 1 cold rolled style k box - 14-5/16 inches width x 37 inches height x 3-7/8 inches depth amp rating=200 Sheet steel enclosure. Single Keyhole mounting Just one keyhole at top and bottom for easier mounting and leveling.Steel back pan provides positive, reliable breaker mounting.Single-piece silver flash-plated copper bus provides great conductivity throughout the entire product line.Drywall marking on enclosure indicates proper mounting depth for flush applications.Only one panel for either application no modifications necessary.Straight-in wiring saves labor and material.Extra 1-1/2 in (38.1 mm) knockout for bundling provides for easier installation, less installation time.

200 amp breaker panel