Already bought my setup. I measured my TB outer diameter. It was 3.25 like WillWren'* diagram shows. I bought a silicone blue 3.25 to 3 inch reducer with 2 stainless steel t-clamps. Altogether - $28.20
I bought the filter for $58.60 from ajusa.com it came today actually. I had to wait about 7 business days.
Just got home from autozone and they had both pipes. The chrome really did just feel cheap. The aluminum was 5 bucks cheaper and just felt like such a better pipe. Cost me $40.
I spoke to sprectre formance themselves and they stated that it doesn't matter much which you pick because once you hit the gas there will be enough air flow to cool it down quickly. The guy said they concluded with those results after running tests with aluminum pipes and the ABS chrome pipes.
I will probably have to trim the alminum pipe down. I will custom make a plexiglas heatshield at work. I work at a hardware store and my boss said he'd let me work on making the shield in the back room one day