Which Subwoofer would you choose?

Hello everyone I’m seeking some advice on which subwoofer would be ideal. First off my tv room size is rather large, 20x20 connected to an open kitchen currently I have (2) Klipsch RP280F towers and an Onkyo TX-NR708 receiver, my budget is around $275.00 (Shipped) for a sub I found these 2 subs used locally both in good condition

Velodyne VRP-12 12" $120.00
Velodyne SPL-1500R 15" $275.00

I’m not sure if SPL or VRP is better? or if the prices of these are not worth it? Can I get something better for $275.00? any advice would help! thanks in advance.