Engine tune questions

[H8NSKPAUL]

Hi guys, me & a mate just bought an S12 and have done a huge amount of work to prepare it for next year. As can be seen here in the photo's




We want to use it for drifting so we have caged it all up, bucket seats, and welded the diff up to name a few mods. We have a few questions about engine tuning. We have fitted a massive FMIC so have increased lag.
How do you increase fuel pressure? can you fit a valve to restrict the flow back to the tank or is a 255lph pump the only way to go?
How do you increase boost to match fueling?
How do you know if it is running lean or not?
What offset and centres do the wheels have? or what oyher wheels fit? ie rover 200?
Many thanks for your advice in advance.
Hans