Brunswick Superspeed are a fantastic playing cushion. Diamond "black" K55 cushions are the same profile, and play very similarly, at around half the cost. However, the Diamond cushions have a strong rubber chemical odor. It may not be noticeable in your environment, but it could be a consideration, if your table is in your living space.
There are other companies that offer a K55 profile, but you have to be very careful. Diamond is the only profile that I have found to be a fairly exact match to Superspeed.
Championship (MBS) and others are not the same profile. In fact, if you install Championship K55 cushions on the same sub-rail, the nose height will be nearly 1/16" lower than that of Superspeed cushions. That's not a bad thing, if you like your table to play springy. However, there is a possibility that balls could hop on rebound, once the cloth gets dirty/worn in.
If you are hiring someone to do the work (recommended), DO NOT buy your own materials. Tell him what you want, and source everything through him. It will likely save you money. If he would prefer that you supply the materials, you should probably find a new guy, as he's not reputable enough to have a relationship with distributors.