Thanks everyone for your response! I quickly posted this late last evening and was a little tired to say the least. Today I thought of a few more details and would like to respond to some of your comments.
My first goal with the new mufflers was not to alter the M3W in any way. I also planned (already done) to store the original exhaust system so they could always be put back on to make it all original. The originals were simply taken off at the clamp and the new ones clamped almost at the same area. The cats were left in. So again, if ever needed everything can be put back to original specs.
When I finally decided on these Magnaflow mufflers, I had spent a considerable amount of time measuring and remeasuring to make sure they would fit on the existing brackets and fit inside the original heat shields. The Magnaflow mufflers at 14" in the large diameter area just fit inside the support brackets. So I made cardboard patterns (front & back) of the support brackets to precisely fit the inlet and outlet on mufflers. This takes a lot of time and like Grockle mentioned in his excellent blog on fitting his Stage I system to "mock up" making sure everything is in perfect alignment. This is so important on an exhaust system especially on a high torquing M3W.
I thought of maybe high polishing or even bead blasting the big Magnaflow mufflers, but decided to just polish the welded areas and leave well enough alone. This took plenty of time as is, but I think they look nice this way under the heat shields.
Early this cool morning, I just couldn't help myself and decided to take the M3W for a little cruise to Sugarcreek and get some gas. The deep valleys were really chilly at around 40 degrees, but I really enjoyed the 12 mile trip. The M3W sounded so nice with that smooth deep tone Magnaflow is famous for. The M3W ran perfectly too - something I was concerned about with the new straight through exhaust system.
So to quote greenteagod...
"i wonder how many buzzards worth of power you'll pick up with them?" What a great line....i feel its really now quick on its feet and plenty of power. I think there is some gain even if it's all in my head! Grockle told me today it will only get better too!
Does it run cooler. Yes indeed!!
Grockle also asked me if I was happy with the results. I told him I'm thrilled! There is always a risk when doing any modification. Things you overlooked or something expectantly comes up. Murphy's Law. This time everything worked out...worked out very well indeed!
Right now, I don't plan on making any of these on commission. I would be glad to help anyone as they really need to be precisely custom fitted.
I was thinking if Magnaflow offered these in 3-3.5" diameter it would be just perfect for the M3W. At that size a guy could fit them in his sleep...lol. I may contact them after more testing.
Well here is my first video if it loads correctly. More to follow and a special thanks to Grockle and each of you!
High Noon Speed Shop
https://youtu.be/mBGaXEF5_CM