Thanks Ian Mc.
I've tried the system loosely and yes, I will add silicone on male end of tubes with clamps when I do final tightening. What about the spring held 'y'pipe joints ? Not sure about these. Do you recon to keep front header loose while assembling the rest or bolt up first? Thanks for input.
Tallpaull I'd rather follow advice from a member whose fitted before rather than a company who omits to put in instructions! Although to be fair, the Black Widow stuff is well made and lines up correctly on the DL.