Still using stock tires on my truck, but it's due to the spec class rules. I honestly like how they work on the tracks I run on, but I've seen a few people reverse the direction on the rear tires for a little more aggressive bite during acceleration. I've not tried it yet, and they were quick to switch back to the standard direction.
In the pro class the guys are cutting their treads with a dremel for more side bite. It really depends on your track conditions, look at what tires the experienced racers are using and see if there is anything you can do with the stock treads to mimic that pattern. If you've given up on the stock tires, it beats throwing them away for something new. I'm getting ready to order new tires, when I do I will try to put something together on how to do it. Honestly, I've never done it so I have no clue how well that would go. I may consult with the pro level drivers at my track and see what they say.