Shop around the parts forum here on NICO. I just got a set of headers for $75 shipped.
You really dont need the exhaust just yet; the intake is cheap too.We already have a 2" mandrel system from the cat back stock.You can get rods and pistons from
http://www.nismoparts.com and they are cheap. Here's the part no's:
12010-30R10 std. grade 112010-30R11 std. grade 212010-30R12 std. grade 3
12010-30R72 oversized 0.50mm12010-30R73 oversized 1.00mm
The grades have to be mached with the ones on top of your existing pistons (the stamp on top of your piston says the number). Oversizing is only if you have to have the cylinders bored and honed for a rebuild.