I ran a full 3 inch TTi system on my 1970 Dart, mild 360/727, and I bought the TTi polished tips. Installed the full system from the TTi headers back in my garage, on jackstands on a Saturday afternoon. No helper, just me and mostly hand tools. The old system was a 2 inch that looked like a pea shooter when it was side by side with the 3 incher. Never regretted it for 1 second, sound was amazing and increase in low end torque was huge. I never bothered to uncorked the headers at the track after that and went consistent 13.80s at 100 mph with 3.23 gears.
Yes, it is a tight fit, but well worth it IMO.