What psi do stadard turbo go to

[MY95]

I used to run 21 psi on my ko3 hdi, stage 2 map and intercooler with a straight through. You will reduce the life of the turbo though, I'd recommend fitting something bigger such as a Gt2052 or an IHI rhf5. Alternatively, you can go down the vnt route and fit something like a Gt2056v  There's loads of information in various project threads and the guides section if you want to read up on it.

After a straight fit one what good strong

There are no straight fit ones unfortunately! Need to get the welder out to fit any other bigger turbos
Id just keep it stage 2 until the turbo blows thenget a gt2052 or similar and go stage 3 then