as long as it's aligned and tightened properly, you won't have any problems.
run as much boost as the motor can take, it's not gonna leak because of that. however, backpressure could find an escape route through it if it's the weakest sealing point in the system. but again, put it together properly and you won't have any issues
You don't need equals. Just go with unequal length shorties. I machined my own V-bands, but you can buy them and convert as said above. The BBK's have been the most popular header for the diy kits. Do some reasearch on turbomustangs.com They have a dedicated DIY forum.
A forum community dedicated to Ford Mustang owners and enthusiasts. Come join the discussion about performance, production numbers, VIN decoders, modifications, troubleshooting, power adders, DIY tutorials, and more!