Definitely the way to go when installing it doing the 5 bolts on the mainfold. Like @breadstick said we both of ours together and it was much less hassle going through the top.
Although we still had to go under in order to mount it which was a bit hard to tighten down still.
But installed well and relatively easy after we got it going, very happy with the product, great and feels very high quality. I couldnt be more pleased.