wow meaning you baught at 6000km only! ... self import or bought from dealer ?
I assume you might have already changed its engine oil and oil + air filters ..
I can't say about tuning.. but ..
the original iridium plugs have a very very long life and at 12000 mileage its not required. mine is at 21k , talked to a mechanic at filter house and also consulted the guy i got it imported from and he said no need . Although he advised to get throttle body checked and cleaned (if needed) at regular intervals.
to be safe. Get its plugs and throttle body checked from a good and "honest" mechanic who has experience of JDMs, who will tell the condition honestly and not ripoff you to get them replaced and cleaned just to get money.