You should be over 400 now but if not then there is always pullley+tune, or just the tune (if you dun wanna go pulley yet.) there are headers, cams, mid-pipe.... bunch of other things that'll safely (for the most part) get you more power.
If by "safe" you mean warrantee friendly, you might want to stay away from a tune (although an ECU reflash should be safe from the dealer detecting). I'd recommend an Accufab TB or have your stock TB ported. My dealer was fine with the Accufab (netted me about 10rwhp) and a ported stock TB would be impossible to detect unless the inside was examined. I'd suggest a ported blower (also very difficult for the dealer to detect), but you would need a tune. I would think with your intake, exhaust and a TB you would be over the '400' mark. Of course you could also consider a midpipe to be sure. My catted X-pipe was fine with the dealer as well. No guarantees with yours, though.
Best of luck! By the way, have you dynoed your car with those mods yet? If so, how close are you to 400rwhp?