I like the Sundown Audio stuff except they tend to be large. Great crossovers. I tend to stay away from arc as you can get the same amp cheaper. And by same I mean dang near exactly.
If small formfactor is a necessity, the JL and Alpine class D fullrange are hard to beat with the PDX and HD/XD lines.
Zed Audio etc.
Honestly just go to woofers etc, sonic electronix or millionbuy and put in your budget and look at the selection. Same at crutchfield. Remember that amplifiers have pretty much become a commodity. So get the power amount you want coupled to size restrictions if any along with budget and determine if a specific model/brand is your favorite. You should be happy.