I don’t think that it’s a good idea to chase the 13-500s hp numbers. As you can see even with all those mods the ZL1 only managed 560 rwhp in this article, while the 500 usually sees 600-620 rwhp stock. If the 500 adds a pulley and tune and they are sitting at 680. So you get the idea. Instead I think you are better off to work on getting your car to be more efficient, learn how to launch and drive it. Last week a member here drove a stock ZL1 with DRs to an 11:50s pass. That pass would beat 90% of the stock 13-500s out there. IMO this is much more impressive than somebody throwing a bunch of dollars at their car to boast about hp numbers.
2012 Ford Mustang 5.0. Brembo, 3:73s
2012 SRT Challenger 392 auto 12:40s 112 stock
2010 SS, LS3, Cammed, LTs, 12:20s
2004 Redfire Cobra, Pullied & Tuned
1986 GT, Ed Curtis 347ci, 11:20s motor. 10:30s 100-hp shot