Keep in mind some have a harder time feeling 20 hp difference with cat delete. I figure you spent 800 already and don't want to dump that and get an xpipe with HFC but it may be good for a few more as even though the secondaries are 200 cell, they are ceramic and less flowing than a metallic HFC 200 cell. Although probably not much.
Only other thing I would say is make sure there is no exhaust leak or anything around the header flanges, make sure your air filter is not too dirty so you make sure there is no air flow issue. Make sure your spark plugs have been changed recently. With all that you should definetely feel a good difference