I've used a few, I'd NEVER use TTI/CPPA again, total nightmare for any kind of maintenance on the car.
Maddogs were ok on a low deck but required some work.
Proparts were also ok on the low deck but required some work.

I'll never do any of this again. If I ever own another big block a-body it will have a Bondobob front suspension and custom headers, or the Hedman fenderwells or TTI 2 1/8 step headers with the Bondo front end.

TTI 2" did have great performance though, and Ive heard the Hedman fenderwells are even better for power.

My next build will probably be a stroker small block, much easier.