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2005 330i manual transmission performance package
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I would avoid epoxy for fixing reinforcement plates. Silly half-arsed solution. If you're going to put in all the effort, might as well do it properly.
If you really want to make the car future-proof, you're best to also do topside reinforcement in addition to the bottom reinforcement plates. That would involve cutting up the boot floor and at the very least adding in weld plates that connect the RACP to the chassis rails. If you want to take it a step further, also add the weld in beam that connects the chassis rails for extra rigidity. Also, no plates are required there per se, but it's worth doing additional stitch welds around the trailing arm pockets.
No affiliation, but CMP Auto Engineering ones are what I'm going with for my Touring. Even if you're going with some other brand ones, their tech articles are a must-read to get a good idea of the nature of the issue. Most comprehensive write-ups on it that I've found anyway.
Epoxying bottom plates as a preventive measure (no cracks present) isn't silly. If done right (using an appropriate industrial-grade epoxy), it's better than welding as it binds across the entire surface, not just around the periphery. There's a lot of room for arguing if this is enough or even necessary, not so much when it comes to comparing the overall strength of binding.
 

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I’ve personally never seen a 325i or 330i with cracked subframe mounting. It’s always the differential mount. On the other hand, every e46 m3 approaching 100k miles I’ve seen has cracks.

People over exaggerate the issue on 325’s and 330’s. If you had a 1998/1999 e46 you have a chance of cracks starting.. In rare case’s.
 

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I’ve personally never seen a 325i or 330i with cracked subframe mounting. It’s always the differential mount. On the other hand, every e46 m3 approaching 100k miles I’ve seen has cracks.

People over exaggerate the issue on 325’s and 330’s. If you had a 1998/1999 e46 you have a chance of cracks starting.. In rare case’s.
I dunno about that.
My 328i had a destroyed RACP at 100k miles. I got BMW to fully cover the repair back in 2006 or so.

My 2001 M3 is at 130k miles now and it is fine. I did reinforce with the Mason brace a few of years ago.
 

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I dunno about that.
My 328i had a destroyed RACP at 100k miles. I got BMW to fully cover the repair back in 2006 or so.

My 2001 M3 is at 130k miles now and it is fine. I did reinforce with the Mason brace a few of years ago.
A 328i is probably going to be the 1998/1999 like you quoted in my post. I’ll say it again, 325/330.

Also regarding the M3, they tend to crack at the front right mounting point first. A very small hairline crack. I’m sure a bunch of dust/ grime is covering thar area so it can be hard to spot.
 

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2003 M3 6MT Slicktop
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If you had a 1998/1999 e46 you have a chance of cracks starting.. In rare case’s.
I wouldn’t say it was “rare” in those cases at all.
 

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A 328i is probably going to be the 1998/1999 like you quoted in my post. I’ll say it again, 325/330.

Also regarding the M3, they tend to crack at the front right mounting point first. A very small hairline crack. I’m sure a bunch of dust/ grime is covering thar area so it can be hard to spot.
I disagree. There was a massive subframe thread on this forum back in early 2010 with tons of 325/330 with subframe issues.

No E46 is immune from this, it all depends on how it was driven. That includes convertibles too.
 

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I disagree. There was a massive subframe thread on this forum back in early 2010 with tons of 325/330 with subframe issues.
i’m extremely familiar with that thread. it’s almost all 323/328.
(not saying it doesn’t happen to 325/330s but that thread isn’t a good reference for your point.)
 

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i’m extremely familiar with that thread. it’s almost all 323/328.
(not saying it doesn’t happen to 325/330s but that thread isn’t a good reference for your point.)
If you could find the thread again, I'd be curious to take a look. According to analysis from CMP, ALL E46s are subscetible to this, the engine size doesn't really make a difference except more power=cracks come sooner




All E46 3-series models built roughly after Feb-2000 share the same Rear Axle Carrier Panel and there is no E46 entirely safe from ‘subframe cracks’.
 

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If you could find the thread again, I'd be curious to take a look. According to analysis from CMP, ALL E46s are subscetible to this, the engine size doesn't really make a difference except more power=cracks come sooner
again i’m not saying it can’t happen to 325/330s. i’ve been saying this for well over a decade before the guy at CMP got his first E46. it’s just nowhere near as common as 323/328/M3s
 
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