Suppliers etc etc
Under slung or side pipe exhausts can be fitted to the Sumo, with most builders fitting twin sidepipes.
Pilgrim supply 2" inlet single collector stainless sidepipes and perforated sheet guards.
These are good quality but not quiet enough for IVA as standard and require further baffling to reduce the noise level sufficiently.
They also don't have a rolled edge on the outlet edge so need trimming up here too to add a radius.
Other manufacturers are available such as Custom Chrome in Nuneaton who supply sidepipes in various diameters and collector options, again in stainless.
A very popular option is their quad collector which is a single 2" inlet piping to 4 pipes which exit the body just behind the front wheel and enter the sidepipes as one large diameter pipe. These are very common in the Cobra replica world!
The sidepipes are joined to the manifold with a separate section of exhaust pipe. I found that the build up of tolerances on the manifold outlet, joining pipe and side pipe had the effect of kicking out the side pipe at the outlet end. This necessitated bending the joining pipe back toward the cars bulkhead to improve the angle and ensure the pipe sat parallel with the side of the car.
Sidepipes need to be suspended on brackets affixed to the chassis and isolated with rubber bobbins. There is lots of conflicting detail on how many brackets and bobbins to fit on the Cobra Club forum. Personally, I've two brackets per sidepipe and that works fine without fracturing or issues that some others report. The issue is fixing the sidepipes TOO rigidly so that the movement of the engine and exhaust manifolds through normal use causes stress fractures.
I recommend reading up on the forums before deciding on your setup.
The heat shields are fixed with large jubilee clips which works much better than it sounds and looks fine.