Sanderson DD7 Headers or TTI "step"

I have seen this posted before but there were no answers ...
Has anyone installed a set of Sanderson DDY shorty headers? I am ready to do some winter upgrades and I am going to install the TTI "step" headers or the Sanderson DD7's. I like the DD7's but I would like to know first if there are any install problems. I have a 1968 Dart 340 with an A833 4-speed. Still using the "Z" bar, no power steering , no power brakes.
Sandersons are 1.500 Dia. pipes into a 2.500 Dia. collector. TTI stepped headers are 1.625 pipes stepped up to 1.750 into a 3.00 collector. In either case I will take to a muffler shop to connect into my old under car system. I have off work this week and would love to get this done asap. Neither option is cheap so I would love to learn from someones experience.