Hey guys

Im brand new to welding but would like to build a turbo setup for my camaro.

been watching youtube and reading as much as i can... but have a few questions.

The setup will be either SS or mild steel. schedule 10/.109" thick wall.

Most will be 2" diameter.

Questions:

1)What technique is best for migging the pipes? High current/heat bursts all around? Zigzag/C/U/E type patterns?

2)Can i grind the welds smooth or will it affect the integrity?

3)Do i need a gap? If so, what size?

Im sure ill have many more questions, but thanks in advance for helping me out!