I have one and it's fantastic to me with stock settings. What kind of grip are you looking for? Corner exit or high speed?
I actually came here looking for a tune myself but seeing as nobody's put one up yet, I'll share a variation of one of mine. It's not my exact tune - it's quite basic, but it would be good to get some feedback...
Amemiya RX7 '06
Where can it be improved?
the secrect is out!!!!