As someone else mentioned, 3Sigma Audio I.R.s are sounding pretty good right out of the box. I use them for modern metal, chug, djent sounds and I was immediately impressed with the 6 pack i bought. Diezel, Mesa OS, Engl being my faves. Minor tweaking here and there. Thats not to say I couldnt make the stock cabs sound great, just took more time to really tweak them. Theres a discount on 3Sigmas site if you buy 6, and I thought it was absolutely worth my money.