Yeah, I already thought about the VG's but I figured enough was enough for this particular build. It's Jeep 4.0 HO I6 with MPFI (that explains the weird bump in the top of the intake port for the injector). It's really limited to about 5200 rpm anyway and my biggest concern was low lift flow. It's rated at 190 from the factory but I'd be thrilled to see 210 to 220.