"These build journal entries are part of a special series on the development of the E46 M3 V2 Carbon Driveshaft by YFCM Composites. 

This journal entry covers my thoughts on the stock 420G, my previous experiences with the V8 and V10, my driving impressions along those of another tester, Ryan, who's been able to tear it up down under in Australia."
- Matt

My history with M manual transmissions. 

I've always felt the stock BMW manual transmissions really weren't all that in stock form. 

I used to own an E92 M3 6spd back in 2012. 

The clutch was rattly, the flywheel felt heavy, the throws were long and felt like row boat actions through mushy bushings and that would crunch 2nd gear if you felt like showcasing some sleight of hands.

I tried a quick fix with the F10 M5 weight shift knob and it made it OK.  

I heard a DCT snap downshifts and the rest was history - this car was gone and made way for a PDK 987.2S. 

Pardon the OG photography, these were different times. 

The 420G is worse. 

This Getrag transmission couldn't handle as much torque as the GS6-53BZ with its single disc clutch. For this reason, it's often swapped for the 5 speed found in the older US E36. 

My 420G was previously fitted with a HD Sachs clutch to sustain Supercharger power levels: it wasn't fun either. 

Progress doesn't work like that [...] or does it. 

This is admittedly unfair criticism: I bought into the E46 M3 going backwards in times.

It was still an improvement over the US E36 M3's 5 speed transmission with an extra gear. The extra torque multiplication from tighter ratios made it a much faster car than the E36.

We can fix the past (!). 

The carbon fiber driveshaft was first introduced to the BMW M world in 2015 with the introduction of the F8x M3 and M4. I previously touched on this here. 

This car featured solid mounted subframe bushings, lightened DCT flywheel and a a one piece carbon fiber driveshaft. 

It was a chassis masterpiece if you disregard the first MY. 

We're now able to retrofit carbon fiber driveshafts to older BMW Ms thank to engineering focused brands such as YFCM. 

My experiences with YFCM's driveshafts on my V8 and V10.  

I've been running the YFCM V2 carbon driveshaft variants on my E92 M3 and E60 M5 for 30,000 kilometers combined. 

You can read more about my V8 DCT impressions here.

Everything is sharper, everything is smoother - and thus, everything is faster. 

Within the framework of automated manuals and double clutch superfast transmissions, the carbon driveshaft mostly has the effect of an efficiency multiplier. 

The current state of my E92 DCT makes it the pe·nul·ti·mate BMW M transmission: there was nothing ever more efficient.

They are both, ahem, well, they both have a Drive mode (!). 

The E60 SMG3 has the added layer of making the SMG actually livable in low gears and reverse, something the DCT doesn't have many issues with in comparison. 

It made the Drive mode useful in some instances - which it really never was. 

Still, I didn't have hands-on experience with YFCM's carbon driveshaft on any 6spd BMW M application. 

No matter what I like to think, these 2x cars don't have a third pedal and will never feel like a manual, even the SMG3.  

The E46 M3 experience. 

I had the carbon driveshaft installed over the Summer and was able to drive sporadically the E46 M3 through the Fall. 

The 420G and the E46 M3 always felt especially raw: you can hear mechanical noises all over the spectrum of clutch operations. 

It adds character - although it never felt really efficient. 

The carbon driveshaft fixes it.  

The E46 M3 6spd carbon fiber driveshaft provided all the efficiency benefits I previously experienced most specifically with the SMG3 V10:

• The throttle response is improved
• The connection to the rear is improved. 
• The chassis response is improved. 
• The low speed clutch operations are smoother. 

There's no more softness or hesitation between shifts as the powertrain simply doesn't move as much anymore thanks to the 1 piece tube design. 

Click, click, boom: the bolt action. 

Because of the 3rd pedal: a new layer to the experience was added. 

The carbon driveshaft enhances the raw nature of the E46 M3 and its 420G. 

Whenever you find yourself catching a gear: it feels instant with an extra layer of mechanical feelings is added. 

You can feel the linkage move around.

You can feel the clutch grabbing the flywheel.

You can feel the rear end bolted to your hips. 

This is the greatest benefits of all across my experiences with carbon driveshafts. 

It feels like shooting a Springfield at the range, or in COD.

Ryan's experience. 

His perspective will be different than mine as he previously had a DSS/VAC carbon driveshaft fitted. I know from research in the M3 V8 world that their design was a failure. Ryan confirms it. 

This is Ryan's review of the driveshaft. I added titles to help situate his points and put how many times he said wow in italic ahah (thanks for the enthusiasm Ryan!), 

---

My car's condition. 

Finding Matt. 

Wow this looks like its made to a much better standard & compared it side by side with vibrating VAC crap shaft.

My driving tests. 

Wow this feels so solid direct and smooth.

I said to myself wow, this is how I always thought it should feel: no vibrations, just solid feeling & amazingly smooth delivery. It is complimented so well with the CAE street shifter, what a combination!

My track day tests.

Wow, what a driveshaft. I would say it would feel just as good even if you didn't have solid diff bushing , cradle etc, like me  as its still silky smooth with solid mounts.