Im pretty much doing the same thing as you. I have a set of gt40p heads sitting in my garage. I bought an explorer intake and put it in myself. When buying an explorer intake there are quite a few things you want to look for that will make the job ALOT easier. You should read up on them. I got my explorer intake for 200 bucks and it looks brand new, cant beat that price. And its the same thing as the cobra intake.
Now to compare the cobra to the typhoon, I asked myself this question not too long ago, and the decision was pretty simple. The typhoons' runners are not as along as the cobra/explorer intake making it a higher rpm intake. I was looking for off the line action, more torque, so I went with the explorer. Like said before forget all the "its made in china" bull****, look at your budget and pick the one that fits your application, do you want more low end torque? Or hp up top. The typhoon is a good intake but I agree it may need some work done to it to make it just right for your combo. If you get the explorer it will also need some work done to it, If I were to go back and do my intake swap again, Id just go ahead and buy a new cobra intake from frpp and call it a day.
As for the swap, id do the heads first, I really didnt notice a big gain with my intake, I will say it pulls alittle faster down low, and my et's went from 13.5 to 13.3, but still not as good of a gain as I was expected. Buy all the gaskets cause your going to have to anyways, and when you do the heads, instead of putting your stock intake on, just put the cobra on. The intake will be a nice mod, but with the stock heads itll be choking and you really wont "feel" a difference.