Have my Trickflow for about a year now (powder coated silver) and no problems. Got it from Summitt with good customer service on the order/delivery. I chose it based on the numbers posted, price and the look/finish. Back when I did my research, the Pro products unit had complaints about the finish and whistling issues? Both are an improvement over stock (given no issues).
Either one is fine. The plenum has zero moving parts, so the only quality aspect is casting quality, and my Professional Products throttle body is smooth as butter and I have zero complaints.
Neither of them should whistle if you install them correctly. I have the TF, and I actually bolted up the TB to the plenum before I installed it, so I really could skip a step when I installed it the next day!
My car has had roughly 20k miles without any problems related to the TB/plenum. (Knock on wood), but I did buy it through summit so they will help me anyways if there are any problems...
I used a 75mm PP throttle body and Plenum on my 02 with 0 problems, easy install. I would not waste another 100 or so on another product, Just not worth it in my opinion.
im actually in the market for buying a pp plenum/ tb since i have to swap out my manifold. This thread came just in time so i can hear what some have to say.