I have a 2001 GMC Sierra and I am looking to buy plugs, wires, a throttle body spacer, and I am going to throw an exhaust on as well. I have a K&N intake already. What do you guys suggest?

 

I would get Bosch platnum 4 plugs and as far as the exhaust goes i would put on a 3 inch true dual exhaust with 8 inch cherry bomb glass packs.

 

a throttle body spacer will do nothing for you but make noise, they only add horse power if its carburated

 

NGK Iridium spark plugs are the best choice for these motors. If you want to keep your HP, single 3 inch cat back with 4 inch tips will sound good and you wont lose your bottom end torque. Free flowing exhaust does not give more power. These motors love backpressure. And the spacer is optional. I do have it. I only have a few more add ons and I believe it helps only in the MPG. On the highway I get about 22 MPG, and I have more than 200k miles on my motor.