556882 by Sachs are standard ones. They will fit, but don't expect much from them. Cannot say a word for Bilstein, just have no experience.
you could read nice post by one of guys from forum. BUDGET PERFORMANCE SUSPENSION GUIDE (Ultimate E46 OEM+ SACHS Setup)

 

I'm a few months into owning my 05 330ci, slowly but surely knocking out preventative fixes and bringing her up to speed. Next on my list is the rear shocks, which appear to be the originals at 116k miles. They are leaking and need to go.

I'm debating between these two kits:

BMW Shock Absorber Kit - 556882KT2

BMW Shock Absorber Kit - 556882KT2

www.fcpeuro.com

BMW Shock Absorber Kit - Bilstein Touring 19103150KT1

BMW Shock Absorber Kit - Bilstein Touring 19103150KT1

www.fcpeuro.com

They both say they fit, the sachs kit says for models with sport suspension. I thought all the convertibles had this? I ran my vin check and didn't see any mention of this so I believe I have whatever came standard on the 05 convertibles. The bilstein kit has "touring" in the name so my concern is its softer or boaty. Anyone have any experience with either of these on the convertible?

Nearly the same price, both good brands. I'm about to flip a coin. Both of them have to be better than my clapped out factory units. Just looking for any advice.

Many e46 owners on Reddit post rave reviews about the Bilstein B4 shocks & struts.

You might be happy with B4 shocks.

I have not installed them in my 325cic, but I will in the future.

 

I just installed the Sachs shocks on my '05 a few months ago to replace the original 173k mile ones. They fit fine and ride great compared to what was in there. I would replace the rear shock mounts, gasket, bump stops, and dust covers which you're at it - parts are cheap and mine were well past their usable life when they came off.

 

Replaced rear shocks several times, always with standard ones, as most manufactures discontinue soprt version of rear ones for E46. Never quite satisfied with them, as they are too soft. Going to try e36M ones, as mentioned in that very informative issue, thanks to @Galapolis BUDGET PERFORMANCE SUSPENSION GUIDE (Ultimate E46 OEM+ SACHS Setup)

 

I had sachs on mine. I now have Bilstein b4. I prefer Bilstein b4.

 

Bilstein is a good choice. It is a bit firmer than OEM.

 

Sachs makes great products. Have for decades. I prefer the OEM ride so that's what I'll be sticking with. You can also guy complete front and rear kits with everything recommended to be replaced. Bilstein are also fine if you're looking to pay a bit more for a different ride. I've had both and still prefer the Sachs.

 

Do you have sport package? This was discussed recently on e46 general page.

 

I went with the Sachs and have been really happy so far. The shocks I took off the car were not rebounding at all so I think anything would have been an improvement.

 

OP, you only mention the rears, but what about your front struts. General consensus is the OE dampers are done by 50-60K, so unless your struts have been replaced already, they're toast. I got my '05 ZHP with 84K. Not only were the dampers done, they were so done there was no sign of the oil that had to have leaked out of them. When I took them off, I compressed them by hand (virtually no resistance) and sat them in the corner of the garage...ran across them a year later and they hadn't rebounded at all.

Anyway...my .02. I went with the Koni Sports (adjustable). Supposedly, on the softest setting, they're a little (10% ?) stiffer than the original sport suspension dampers. And, by being adjustable, you have the option to stiffen them up if you desire.

 

I am pretty picky about suspension. I think Sachs absolutely sucks when it comes to dampers. I don't recommend them for anybody for anything!!

In the E46 M3 community, Koni yellow shocks are highly regarded for people who are not lowering their vehicles. Or for people just using a spring kit.
I think you should look at Konis.

I am running on custom valved Koni dampers coilovers right now (TC KLINE). And I'm looking into even better and more adjustable options. Perhaps Ohlins. Motons, KW V3.
When I first got my 2005 M3 in 2008 with 17,000 miles on it I couldn't rip out those Sachs dampers fast enough. HATED them! Within 24 hours I was ordering entry level KW coilovers which also use SS body Koni dampers.
Just say no to Sachs.

 

Yep, gets Sachs especially on a vert with sport suspension. Koni are overrated and over priced. You won't be a phony unless you buy Koni. See what I did there? 😆

 

I have replacement Sachs sport suspension shocks on the rear of my cabrio and they seem fine, now maybe quality has dropped in 5 years......?