I run 551 rwhp uncorrected and tow all the time. You may need or want a bigger charger to cool egt's. If all you want is 500 then just get a switchable program so you can turn it down a litte when towing. I leave my hot+2 on kill all the time and may hit 1050 egt's up hill with 10000 lb. trailer in tow. I do have a bigger turbo though.