This is a popular topic.
Headers can be a nightmare for even the most experienced fellow due to the fact that often times they just won't fit without a sledge hammer!
Then, you burn your plug wires from time to time, blow gaskets, and drag them on high speed bumps and other road obsticles.
Your engine can breath much better and therefore make more power. Your engine is after all basically a large air pump. The more air you can get it to pump in and out the more power you can make.
Now, there are expensive headers and cheap ones. For myself, I gravitate to the cheap ones, but I typically suggest other people buy the more expensive ones. This is because I don't mind banging up my knuckes, but would hope I could steer you in a direction to bang yours less.
Between several of the members here, we are running different brands of headers.
To my most pleasant surprise, I recently installed the cheapest non-emission headers headman had for the L98 on my 90. They went on EASY, no mods to the headers or the car. They stay clear of my plugs and wires, and have been easy to retighten as needed to keep them quiet.
I paid about $100. They have baked all the paint off now, and have a nice discolored and surface rust thing going on.
Ken can tell you about his header experience. He went for some nice coated larger tube models.
Right now on the Classified's section of this forum, we have a member with some of the stock style ram horn manifolds for sale by make your best offer. Check those out. Less headaches, and plenty of good looks.