I am going to replace my pre-cat with an HKS DP that I purchased. I was wondering if I can install a cutback after that without needing to work with fuel management, boost creep, ect since I'm leaving the main cat in there.

 

You'll be fine. You only need additional fuel if you run higher boost levels. Creep won't be an issue as long as you maintain a cat.
Consider heat-coating the downpipe or header wrapping it before installation. Going from the stock pre-cat to a downpipe shielded for heat you should see a nice difference in underhood temps.

 

To add to what Sgtblue said make sure you get a brand name DP and as far as coating goes I highly recommend Jet-Hot Coating.
The forsale section is the best place to find one.
http://www.jet-hot.com/

 

Thanks for the answers. I planned to buy an HKS and jet coat it before installing.