a friend of mine who is a mechanic said that even if i put a new maf, tb and cold air system on my t-bird, i will gain only minimal hp because of a "funnel" effect, with the heads not being able to process the extra air. the effects of the added maf and all would doubled, if i got the pi heads and intake. so if i just get the maf, tb and tube, will i see at least a desent hp gain? how much? (this is for a 4.6 V8, 95)

He's sorta right, you won't get a huge increase, but the heads do have room to process a little bit more air. If you optimize everything from air filter to throttle body, you will get a max of about 10hp give or take a couple. You would get a higher gain from the same modifications if you had PI heads. No amount of exhaust modifications are going to get you any more significant gain than the intake modifications. Your engine can only push as much air out as it takes in. These differences are what gave the mustang 225hp as opposed to the T-bird's 205hp. About 10 of those horses came from the better intake and the other 10hp came from the true dual exhaust. Hope this helps, Kenny