Should I recap my speakers? If so who can do it?

When it comes to crossovers, resistors should be wirewound, or paralleled film/foil types to get proper power rating. Stay away from metal oxide resistors at all cost!

My personal favorite are still the Mills MRA-12, but I also like Ohmite AG12.  

Rather than arguing about quality of parts. I think it is very important to see what kind of budget that James wants to use. I tend to be more frugal than others here and I’d hate to discourage him from an update. Even with some less expensive parts, he will hear a big improvement from the stock crossovers and really what it comes down to is what the person doing the mods wants to use. 

$4 for the MRA12 😊

Agree 100% will your post.  Many options from inexpensive to uber expensive.  It all depends on how critical the position is, the quality of the rest of the speaker and the owner’s budget and expectations. 

I beg to differ on the sand cast resistors

It depends on the implementation. MRA resistors are wire wound and designed to minimize reactance at RF frequencies.

If the original design was tweaked to include the resistor reactance, changing them could make a difference. Whether that difference is perceived as better is totally subjective.

Capacitor upgrades from 'lytic and mylar to polypro trump resistor changes six ways to Sunday.

What works well in one design may not in another. There is no free lunch.

Agree with you.   No problem with anything you said.