Just curious, what is your compression on all 4 cylinders? what condition are your stock rods/pistons and crank/bearings in? From what i've read on 2gnt most guys are lucky if they can run 8-10psi on a stock block/internals, max i've seen is 12psi. Every engine is different, your internals could be near perfect where someone else may have below-average or visa-versa its impossible to tell... so to say I can do it because others have is far-fetched. Why risk ****ing up your stock rods/pistons/crank and possibly more by running too high boost, run a safe level of boost, save up for a proper rebuild then do it right the first time.

sidenote: What psi did you dyno/tune at? what were your numbers (a/f, hp, trq)?