how much does it cost, and does it give more HP? also how much would dual exhaust cost for a 98 v6?

 

Let's see, for cost, I would check with the vendors. As far getting more HP, no, nothing in the rear-end ever gives more HP, it just allows you to do something with HP you have. If you have no traction, then all the power adders in the world won't help, they'll just make it worse. A locker/limited slip diff will just help you plant both rear tires firmly, as opposed to one loosely.

Ryan