I've used both of these in my previous M-body builds:

1) 78050, Headman Headers
2) 5901, Hooker Competition headers

I would recommend the Hooker pipes, overall they just seem better made. Before installing in the car I had them thermal barrier coated by a local MI shop. They've lasted about 5 yrs of summer only driving, no complaints.

The big difference between the TTI and the others would be that the TTIs do not require you to disassemble your steering setup for installation, the pipe runs around it.