I am running the R700 BD Twins on my 2004 with around 600 HP; I also ran the towing twins. In both cases, I have the wastegate rod turned so the ‘gate stays tight shut, which is the best and proper way to run twins. The caveat is that you don't want egt's over 1250 deg, or 1300 deg. Max. If you do get higher numbers, you need bigger twins or, especially with a 12 valve, head porting and a camshaft (a 1998. 5-2002 and a 2004. 5-up engine also have non-optimal camshaft designs; the 2003-early 2004 HO cam is OK). Part of the recipe should be keeping the boost air cool. This is generally accomplished with a good intercooler like the BD extruded tube design (I am using one) along with properly sized turbos. I run stock head bolts and gaskets; in fact, I have never disturbed them from when the factory built the engine. I don't usually go over 35-40 psi boost but do go on occasion to the 55 psi max that the twins produce. I have used them for three years and 50,000 miles, an incredible record for turbo life on my Sickly Rams.