finally got back to this, thanks for the replies.
So what you are after is a spacer of how deep? with a male thread out of one end to screw into the fixings on the clam and the other end of the spacer to have a hole with the thread to then bolt your undertray, therefore lowering it?
Yep thats what I had in Mind. I have a short TAT version which replaced the standard rear under-tray. I brought some Male-Male spacers only 30mm (M6 thread) as thats all they had to hand I will check to see if it will work OK and then if I am happy I will get some 40mm maybe 50mm. My only concern are the 2 larger bolts (I replaced all the under-tray allen key heads with bolts) and the 30mm gap I will have created, I need something to go there. Other factor for Male - Male was that the Male - Female had 6-8mm threaded section might not be enough. It still leaves me with exposed thread under the car, OK not much but I will try some grease on them to see if that will stop them corroding.
Nickb777 I also have a TAT diffuser, it doesnt have the recessed bit at the m8 button heads like the oe undertray, so i spaced it away by 15mm to give more clearance between the cat and tray.
Used 50mm stainless round bar with an 8.5mm clearance hole, could do the same with smaller bar for the m5 fixings and put longer bolts reaching into the TAT brace/spreader bar.
Could make you some for a small fee at a spacing of your choice.
Thanks that was the other method I was looking at, will keep your offer in mind

. I am hoping though that once I get the spacers fixed to the car underside It should be a easy job to remove and replace the TAT without all the fiddling that goes on at present. Other advantage I hope is I will be able to get a Brace bar below the 3" exhaust and above the TAT without touching.
I do tend to remove my TAT more than normal people as I seem to ticker with the thing all the time
Edited by NickB777, 12 August 2009 - 07:54 AM.