My 2 cents... The three mounts you talked about ( both front lowers and the rear) are what I perceive as the torque mounts. They are the mounts that receive most of the torque as the engine flexes up while your big toe is tickling the radiator cap. I believe they are a very important area to focus on when trying to lessen engine movement. If you swap those mounts with stiffer units, you will get good performance feed back but a lot of vibration. Nature of the beast as those mounts are 'torque limiting mounts'... I went the opposite route on my current build. I installed a "engine dampener" on the left upper location where the fluid filled mount is. I found that helped a ton with no new vibration what so ever, but it felt uneven from the other side during hard launches. And doing burn outs still caused more wheel hop than I wanted. I then Installed a Hasport 88A mount in the right upper location (transmission upper). There was finally some vibration, but not as bad as a complete set of Hasports, or any kind of mount insert kit. Wheel hop was almost eliminated (most of the issue is left in my cheap tires now). I ordered a 66A mount from Hasport to see if I can get the same results but with less vibration. Kind of experimenting with mounts and I'll let you know when I get them. Trying to leave the torque mounts stock so I can still go on long coastal drives and not have my hands go numb from the vibration.
I am not boosted however, current set up is a fairly stock B18C1. I would imagine the safer approach to strap your engine down would be to follow what the guys were talking about earlier in this thread. More power means more chance of ripping mounts out and denting hoods or breaking exhaust welds.
I couldn't imagine running boost on the stock EK mounts. When I swapped in My B18C1, it felt like it was being held down with rubber bands. And this was with all new factory mounts. My bad, wont waste that money again haha.