I just got off the phone with Frank at Driveshaft.com. He told me to send in the old set of axles and $600 and they will upgrade me to the new Level 5 800hp axles. He told me they will hold up to a 26 inch slick. If i want to run 28 inch slicks then i will need the 1,000hp set. I'm happy with that. I will be sending them out soon.