AN EXHAUSTING JOURNEY
The search for a muffler that was throaty but didn't make your ears bleed led to replacing the stock mufflers with a pair of Corsa axle-backs. The Corsas were quite throaty in the top register but overall they were too quiet, even if they produced zero drone. However, a muscle car is about rumbling through the streets slowly with a grumbling thunder gently resonating windows. The Corsas were therefore replaced with a custom made pair of axle-backs which were lighter and also produced no notable drone.
FROM STOCK TO CORSA MUFFLERS TO PROSPEED CUSTOM MUFFLERS
With apologies to Simon & Garfunkel....

"Hello Mustang, my old friend,
I�ve come to fire you up again,
But then the gases softly creeping,
Left the downpipes while still sleeping,
And the rumble that was planted in my brain
Seemed pretty lame......the stock exhaust's too silent"

The stock rear mufflers looked just fine as long as there was nothing round to compare them too. It emits a pretty muted burble which is OK for a stock pipe but it's for noise legislators not muscle car enthusiasts. You can see the obvious difference in the photo on the right.

I weighed the stock axle-backs and was surprised to find the left muffler weighed 16.4lbs and the right muffler 15.6lbs (not that the bathroom scales are that accurate). Despite being physically more compact, both the Corsa weigh just over 20lbs a side and so actually add weight.

The Corsa axle-backs are easy to fit and use the existing hangers. No need to even jack the car up to fit them. Here's the Install...

Firstly unclamp the bracket holding the stock axle-backs onto the rear pipe using a 15mm socket. Now unbolt the two bolts holding each of the front and rear hangers using a 13mm spanner and work the rear muffler off by pulling the clamp and wiggling the muffler at the same time and it slips off fairly easily.

Slip the hangers onto the brackets on the Corsas. Slip one of the provided clamps onto the back of the axle-back after smearing it with the anti-seize grease provided. Then just loosely bolt the axle-backs into place using the stock hangers.

Push the axle-back on squarely noting that the flange is a lot shorter than the Ford item so it's important to get the pipe right. Now slide the bracket flush with the edge of the end of the pipe and snug the bolt up. At this stage, tighten the hanger bolts up but don't secure them. Tighten the pipe clamp up per the instructions. Now you can go and tighten those hanger bolts and then check the clamp again and ensure the joint doesn't move. The left axle-back fitted perfectly for me first time.

You can see the clamp bolt in this photo on the left. Do the same with the right axle-back. On my install, the right axle-back hung a lot lower than the left so I kept removing the front hanger and bending the bracket down that you can see in the photo on the right. I also had to bend the back bracket down slightly until I got the pipes level. Then it was a case of tightening it all up and there you have it.

Now don't get me wrong, the Corsas are a precision piece of engineering and there is ZERO resonance but the fact is that although the burble is slightly uptempo, it's still a little too quiet. It really comes into it's own at wide open throttle but in my supercharged application, that didn't happen often enough so once on, they were coming off! LOL! Before changing my mind, I thought I'd try the X-Pipe.

CORSA X-PIPE
Here's a message from one assembly worker to another and here is the stock H-Pipe in situ.

Here's the H-pipe cut off. Measure twice, cut once! This is wrong as the guy who did it didn't measure. The Corsa X-pipe is to the right

Here it is in situ and all clamped up.

Goodbye Corsas, Hello Prospeed custom-built mufflers
The great thing about these mufflers is they give you a distinct V8 throb in the lower register so you can enjoy woofling through the local traffic and yet still produce no drone. They were built on the car so I can't give you a weight but they're lighter than the stock mufflers. I kept the slip-on fitting so I could replace the Corsas if they proved too loud. I needn't have worried, they're perfect.

So to recap this exercise:
STOCK