Modded Marshall-ish high gain amps will do the trick.. Might be possible on a recto, but I'd have to hear it to believe it.. A Mark IV would be much closer to that sound than a DR, IMO..
Basically, a JCM800 with a OD in front, JCM900 SLX(no clean, but sounds 1000x better than the other 900s), or the 30th anny.. DSL or TSL should be able to get that tone as well, or at least close enough..
High-end you could go Soldano or maybe Bogner... Or have a JCM800 modded out.
But most people(like me) don't have that much $$ floating around to blow on an amp..
Cheaper alteratives.. Laney GH50L/GH100L, I'm buying a GH50L in a week or so, and these sound sweet for that upper-mid thrash tone.. No clean, so not much on versitility..
Peavey 5150 might do it, but I've never played one.. Same with the Carvin MTS3200, might be good, but I don't know...
The thing about IE's tone is it's centered more in the the upper mids, so you have to look for something geared for that.. If you were still looking for a pedal, might wanna try out a Marshall Jackhammer, or something in that vibe.. The Metalzone, to me, is too thin and buzzy for it's own good..
The rest is in the hands.. I think John Schaffer sleeps with a pick in his hand at night, and it twitches in that chug---chug-chug-chug pattern all night.. I dunno how the hell he plays that part in the 1st song on the demons&wizads record at that speed.. Most people can't even play lead that fast..