Toyota 2ct engine

[Bonavia]

I have a 2003 Tata Safari with a Toyota 2ct engine installed on it. The engine was a mess and we had to rebuild the whole thing !!

The turbo was also a mess and for us to save money we re board it making it bigger. I have a few questions on the turbo set up.

1) How much can I boost it for this engine ?

2) Does installing my original Tata inter cooler help with power ?

3) How do I decrease the turbo lag ?

4) Does the original turbo have a down valve ?

Thank you !!