OP,
At 90,000 miles, your OEM struts likely are close to the end of its useful life, which might be why you felt the ride is harsh.
While I enjoy good handling performance, I opted to add sway bars rather than sport springs/struts exactly because I didn't want to compromise the ride quality of OEM struts.
I am very happy with the combination, you may find a new set of OEM struts ride nicely compared to your 90,000 miles worn out ones.
Also keep in mind that softer sidewall tires will make your steering/cornering vague, I put Falkan ZE512 tires on my previous car, an 1996 Integra GSR, the ride definitely softened, but the handling took a nose dive even just in regular daily driving.........
I now run the Bridgestone RE960 Pole Position all-season ultra performance tires, loving every minute of it for the perfect combination of performance, comfort, quietness.