Nice to see a fellow masshole with an M5 close to me! I am in Fairhaven.
Those are the exact exhaust brackets I bought, make sure you get new bolts too, you will need them. You may also want to inspect the small metal clips that hold the O2 sensor wires to the heat shield, several of mine were rusted out and weren't even holding the wires anymore, it's a cheap addition to your order and LIFETIME from FCP!
The more and more I read, the more and more I think that the hesitation may be a "thing" with this car, as many many people have replaced tons of parts only to have it still be there. Others say the only way to somewhat make it better is the Evolve Alpha N tune, or another tune. I had some vanos hesitation in my E46, but it wasn't nearly as bad as what I am experiencing in this car, and you'd think that would manifest itself in all gears.
I'm wondering if mine feels worse because my CSB is so so so bad right now. I also think that the rear end suspension rub I felt over deep compression hits, was actually my driveshaft rubbing against the transmission tunnel! It goes away once the car is warm, but there is a deep bump I hit a few times coming into my work parking lot slowly that has caused what sounds like a tire rubbing on a plastic shield, or shock, it was a definite something's moving and then rubbing noise. Now I think what was happening is that the sudden bounce pushed the driveshaft into the transmission tunnel for a quick rub because the CSB is so bad. This is the same type of knocking I get when starting the car and driving it cold in 1 and 2 first thing in the morning, although a slightly higher pitch and louder because of the larger bump.
Car going in on Thursday, I will have them check everything out, and quote me prices. If it's astronomical, I will do what I can myself.
Did you do the diff seals yourself? How bad was that job? Did you need to remove the entire diff from the car? I assume that's the only way to get this done.
And hey, I just bought one of these
(wanted 2 but only 1 in stock) to get the car higher and safer. Seems legit, but have not used yet.
$40 at Tractor Supply, so don't pay $64 on Amazon, or elsewhere. The home depot website also had them for like $36, but they say out of stock online and in the stores.