Probably not enough unless if the dance floor is small and not everyone will be dancing.
At around 300 people, I use 4 tops and 4 bass bottoms.

Depending on the space It would likey sound pretty thin beyond a 30x30 area if that makes sense. If the room had great acoustics you can probably get away with it.

that would be a no from me

probably want minimum 4 of the kw181s

I do alot of Mexican parties. As some of you know, Mexicans like their bass lol. I know 21 inch yorkvilles are the way to go lol.

Would a etx sub work better than a kw181?

the etx subs are better but olny a lil better, the honest truth is you're out of your league here because I've seen Mexican parties and they expect big sound which you do not have.

So this is really going to be about your morals and the pride that you have in the service you provide. You can take the money and try to get over with what you have or pass this along to someone that's qualified.

no single sub in that price range is going to handle 500 people - especially if it's 500 people who "like their bass"

Even the Yorkville 21" sub is not really going to be enough for 500 for a single sub.

How often are you really doing 500 person parties? If it's all the time, you should be making enough to get a proper rig for those gigs - maybe 2-4 JBL SRX828SPs.

If it's only once in a while, then just rent a proper system for those big parties and charge accordingly.

Probably will just rent honestly. May still get 2 181s for my other gigs tho.