Typically it is $200-$250 per corner. That is the average amount. The minimum is $200 per corner. Until HKS sees it in their hands to determine exactly what is blown, they can not possibly quote a repair cost.
What we do is I give you a return number and address. HKS will look at it, quote me, I'll quote you. You can approve the quote, pay us, and HKS will repair - OR - you can decide not to do it and we will ship them back to you at your expense.
To do the repair you MUST go through an Authorized HKS Dealer, which we are.
If you want to proceed I will get a return number from HKS. I will need your full name to get to that point. I also need as much information about what you THINK is wrong with them as you can give me.