Only the customer can decide if a custom finish is worth it/economical or not. Imo, the best deal on a custom finish would be on a real wood finish, but not going to the high gloss finishes. These types of finishes are labour intensive, 11-12 clear coats with sanding in between...hence the cost.

If you're going to listen at high levels, the cast baskets/high power woofers might be the way to go. I believe if you're using a sub, you may not need to though.

Bi-wiring only works if the signal is separated to the various drivers as in an active crossover network, it's a falacy where passive crossovers are concernerned unless the signal is somehow split and the terminals are not running/connected to the same crossover.

Out rigger feet would be a consideration on anything from an M80 upwards, especially if you have curious kids or pets around.

I don't like spikes...hardwood floors under the carpet!!

Half of communication is listening. You can't listen with your mouth.