Yea, unfortunately you can only really buy a superjet pump shoe and not a true Blaster shoe. The Worx 201 is actually a Blaster grate, which people use on superjets, but as you can see it doesn't match the shoe very well at all. A jet dynamics grate superjet grate will match up to it better. If you're set on running that grate, you should fill in all of that open space. I'm not sure it will cause cavitation but it will certainly affect performance.