That is a nice looking Dart. I don't think the tail pipes will make a noticeable difference.
John here is how I see cars like yours. Its just my opinion so feel free to disregard it. You have a damn cool car and looking at the options it was brought new to be a racer/sleeper with that in mind my own personal flavour would be to take it down the day 2 custom route. I would collect all the correct stock parts and have them available. I however would be more than happy with running different wheels, pipes and induction as I think back in the day I would of brought it home day 1 then taken it to get wheel exhaust etc the anyway. so essentially I would have a 95% correct restoration with 5% being all about my personal enjoyment and all the correct parts available for the collectors or for the time you want it 100% stock. My 2cents mate.