Hey 10G.
So just my input..
I can't see any issue with the cheap exhaust.
I bought a $550 playtime exhaust and as far as I could see it was built and welded as well as I've ever seen on an exhaust.

But.
There is an order or you may have issues..

So gauges first..
Imo a scangauge is a good investment.
I've also thrown in a boost, egt and oil pressure in a pillar pod..
But how far you go is up to you..

You need gauges for the mechanical boost control..

Very easy to setup. Set the dawes valve for max boost and then set the needle valve to suit your needs..
Ive taken my needle out for a try.
Its going pretty good..

Youll need mechanical boost control for exhaust and egr block if you fit it..
Id personally still fit the boost control even if you keep the stock exhaust.. the stock ecu is shit lol..