Just go for the Testpipe, I had mine on for 3 Years now and the smell isnt even that bad... I guess it all depends on how picky you are with your car. If you want more fun, noise, and your all about the power go for test pipe, if your conservative and want both but dont like the smell or the rasp go for a HFC. If I were you like you said go big or go home and get a testpipe. When it comes to smog checks it can be a pain but if your good enough you can get it passed with magic. Yah everyone wants to be nice to mother earth but with China, Russia, and all these other countries polluting... isnt really going to help sadly =[ so just have fun while your life last.