T-bolts and standard silicone sizes you can get of ebay the cheapest. Some of the vendors will even mismacth sizes for you. So if you want 2-3" and maybe 2-3.5" they will work with it.
When it comes to reducers or eblows raceparts solutions is a good source, but they are alittle exspensive on the t-bolts.
As far as the piping I dont know if you are fabing your own or what but you can get this off ebay from treadstone or intercooleronly, or whom ever. They have all different size and kits. Just get a universal kit and mismatch it to fit.
You can get a whole universal kit that will include the hoses, t-bolts and piping for 150 bucks. thats all I did, and all I had to come up with was a hose to go from 3" piping to 3-3/4 for the throttlebody and I had to fab up a section to hold the blowoff valve. but that was it. When all said and done I spent about $200, and had left over piping that I didnt use.
88lx Conv. 200K mile stock longblock. Trickflow intake, 42lb inj, Pmas protube,TKO500, 3:27, pypes muffs, Pa Racing tubluar K-member, DIY single turbo setup. Summit aluminum rad, Crane Hi-fire ign, subfames, 17" sc saleen's, Saleen ground effects, SCT tune by Dynosport. 380HP 435ftbs.