Needed new tires and I hated the LRR / Eco tires. I decided to order Yokohama S.drive's (185/55R15 and 195/55R15). Note that these tires are directional, so this combo cannot be rotated.
Impressions after 1k miles. Car is amazing to drive, minimal wheel-spin at full throttle, amazing...
Thanks for the inspiration. I ended up doing something very similar, but without removing the seats:
Sub is under the driver's seat (takes up a tiny bit of legroom). There is some sort of padding under the rear carpeting, screws bit right in. Not super strong, but it stops the sub from moving...