OESSC400

I recently purchased a 1993 SC400 with 56,000 original miles in almost mint condition. I had a written appraisal by a state certified appraiser for not less than $12,000. It's pearl white with the tan leather interior. Loaded with options. I was wondering if there are any performance mods available for this model or would it make more sense to find an SC300 with the inline six or maybe even swap the 8cyl. for the inline 6. The body and interior are almost like knew and although the engine, trans and rear are perfect,it is slow by todays standards. Just wondering. It's so nice I'm not sure if I really want to adulterate it at all. Thank you: Gene