Theres been a lot of good responses from people on ZZP's HV3 insert.

For those who don't know about it, I'll let you read about it on their website:
http://www.zzperformance.com/grand_prix/products1.php?id=214&catid=113

Anyway, found a slightly used one for sale on clubgp for this interested:
http://www.clubgp.com/newforum/tm.asp?m=3704000&p=1&tmode=1&smode=1