Most people who do go with cams are just using the sr16 cams. No retainers or springs required, and you will net about 8 more whp. As for exhaust, if you are set on 3 inch (clearly dont mind the noise), then you get the 3'' VRS piping kit from
www.vrsexhaust.com, you get the longest straight through perforated core magnaflow resonator you can fit under there, and you buy a large oval,straight-through dynomax/magnaflow muffler. You may choose to add a resonated tip if you wish (Pilot tips are cheap and all SS). Have a shop weld all of it together, should total around 450ish. Good luck.
Remember: the longer the muffler/resonator you use, the quieter it will be.
Edit: Apex'i N1 mufflers are also available with silencers, which are very effective at reducing the noise; however, they also cut back on flow substantially and cause you to lose power. These silencers are easily removable so screwing it in and out is no problem.