I like how we're discussing spinal surgery in a thread that is fishing for compliments on the lowest of low suspensions, and the thinnest of thin tires... in a car that already rides firm.
I'm no doc, but it seems like suspension compliance and big puffy tires would be on my short list, if my spine was acting up.
I'm running the SRT spring setup (minus one coil) and the ride definitely qualifies as "firm". As in, Chuck Norris has a firm roundhouse kick.
Just an observation