With tuners this old and with such few capabilities, honestly I wouldn't plan on finding a tuner that would touch it, unless its someone who was one of the OG MSPers from a decade ago.
If you still need to upgrade, I believe it would require a bigger wheel but Mazda6 brakes bolt up.
I scored a pair of the R1s for 60 bucks. For that price I couldn't pass up using them as drag tires. Even though that is not their purpose in life, they'll be much stickier than my all seasons...