Upgrades to my stock 273 67 Dart GT

I'm leaning towards doing headers at the same time so i don't have to go back and add them in later. So id like to hear opinions on TTI vs DOUGS and if theres any specific products from them that would be best/easiest to install! (LINKS would be appreciated).
either will fit with your column shift, although you may need to alter the linkage slightly. tti offers a full length and a shorty-- i know you have to mod the linkage on the shorty, but it's not a big deal.

both sell a quality product, however you can call tti on the phone if you have a problem.

additionally, tti sells a complete exhaust system from the headers back.

https://www.ttiexhaust.com/index.htm
Also I saw on the forums that dumping the exhaust before the bumper is cheaper and sometimes easier on the 67 darts (Correct me pls if im wrong) But what is your guys' opinion/advice on dumping the exhaust early as opposed to taking it all the way to the bumper, pros and cons of each?
pros: it's cheaper
cons: it's loud, you may also get drone at specific speed/rpm

there are several companies that sell tail pipes (the part that goes from the muffler up and over the rear axle and to the bumper) specifically designed for 67~69 darts.

Also curious if once i have headers and mufflers ready if my local shop can do the rest or do i need to buy/supply any more pipes etc
a competent shop should be able to handle an install if you show with parts.

part of the benefit of a complete system such as TTI is that it comes with everything you need to do the install yourself. the connections are slip fit with clamps so you just bolt everything together and you're ready to party.

there are other companies that make complete kits (pypes, hooker blackheart) that are similar and can be installed at home, i know a few the fit is a little more fiddly than others but it's all doable.