100K Coupons

Has anyone created a coupon site with over 100K coupons? We’re at 103K right now and the “Coupon Manager” on the backend of WP is having some serious issues.

We’re going to start importing coupons via the WP API but I’m wondering if that is going to be a losing battle.. Since we will be importing over 500K coupons shortly.

Here are the server specs.
Processor: Quad Core E3-1230v3 (8x 3.3 GHz)
Memory: 32 GB DDR3 – 1600 Mhz
1st HardDisk: 1 TB SATA 6.0Gb/s
2nd HardDisk: 1 TB SATA 6.0Gb/s
3rd HardDisk: 1 TB SATA 6.0Gb/s
4th HardDisk: 1 TB SATA 6.0Gb/s

Any suggestions?

Thanks!