Recommendation for sub upgrade

[frankiev]

Currently using an Infinity Kappa perfect 10 in a sealed cab powered by a jl audio 500/1 and it sounds great ,however when I crank it up it reaches its xmax and starts to make a klacking sound .
I thought about adding a second ,which I already have . But now Im thinking of keeping it to just one sub . As I said it sounds great it just wont go loud enough so Im thinking of just getting something better .
Can someone recommend a single 10 that would sound as good or better and not fart out . It just needs to go a bit louder . Budget is around 2-300