probably wont be putting any more mods in. but if money wasnt an issue should i still get the DP?If you ever plan to top swap or get a cam or rockers & HV3 for your N/A car...get headers...if not...get the DP and take off your front manifold and port it for free with a die grinder.
Gains? 10 horse maybe? You'll lose a lot more low end with headers vs. the DP, but you'll be able to breathe better on the top end with headers than the DP.
IMO, headers...only if you plan to mod more extensivly...if not...get the DP.