If you're running modifed, you want to get packs with the best runtime you can get. You'll need to make sure you take proper care of them to make sure you make runtime. Charge at 5 amps and make sure to discharge to 5.4v after your run and equalize them all at .9v per cell BEFORE your first charge of the day. If you take proper care of your cells, they'll do great for you in modified. I ran a 9 single Yesterday and Randy Caster ran a 6 turn and made runtime as well.