Which is better?

I am about to purchase my Supra in the next few days and I need to know what is the best blow off valve, and exhaust system(up pipe, down pipe, exhaust) for my new car? And another question, what do I install into the engine to give it that "in and out" idle sound. I heard it had to do with racing cam shafts but Im just asking to make sure.

So you're about to buy a 76-98 Supra, maybe you should narrow the list down a bit since there have been alot of changes through the years. Lopey idle can be caused by a few different things but mostly a very large cam with a low engine idle. No such thing as an "up-pipe" by the way.

most exhaust systems are the same. the namebrand doesnt mean a whole lot. just make sure to get a big enough one that the air can get through it easily. i like hks bov's but it depends how much money you want ot spend