I had Tomei Poncams fitted to my Almera GTi SR20DE and these were a plug and play application, with gains throughout the rev range so it is possible to do. For a more track focused application, sacrificing low end for middle and top seems a given.
Re the timing, I don't think you'd be making the power you are being a tooth out. However if you've read similar issue over the pond, it might be work a check.
I doubt you'd gain any more knowledge from here than what Jez would have told you at the time sadly. However I'd personally look towards fueling as no doubt the fuel pump and injectors will be working very hard to keep up.