SME 309 vs SME IV - sonic differences?

Hi - I would like to learn from the experts about the sonic differences of this two arms - I have read all the specifications from both of them regarding the bearing tolerances, materials, etc... but... what is the bottom line regarding sonics?

Thanks for sharing your experience, I would like to take a decision for my arm replacement.

Stereophile did a review a while back. I believe Fremer compared the 310 arm on a SME 10 table. I think it's posted on their website. Look under turntables...He did notice in improvement between the 310 and the IV.Vi.

The IV.Vi has a few differences over the IV you are asking about. The IV.Vi has the same abec bearings as a SME V and different internal wiring from a 309 or a V. The IV.Vi uses Magnan copper ribbon wire internally. Also the IV.Vi has the damping trough as standard, option on the 309 series.

I use a IV.Vi, it's a damn good arm. I am sure a Graham or Triplanar are better, but more $$'s.

Looking at your system, I'd try and go for a IV.Vi or a V. No use skimping here. Not sure what arm you have right now. Also, if you have a 309 today (I am guessing here) have you tried better arm cables? They make a huge difference on SME arms. Whether it's a 309 or a IV, V...
I had a 345 (basically a 309) and a V. I didnt hear a big difference between them using a high resolution cartridge ( ca insider ) and clean phonopre ( custom tube ) The removable headshell is very convienient on the 309 and I preffered using that arm and never missed the performance difference of the V.
my $.02 Rick
I currently own a modified RB300 (Kerry counterweight / Incognito rewire) - I am receiving various recommendations pointing to Morch as a good option as well - goshhh this is though!

Thanks so far for your feedback.
I should add that the performance of any arm is going to be cartridge dependent and the sme works well with a fairly wide selection of cartridges. The big selling point of the V for me is the ease of set up. I change cartridges alot and can be up and running in a couple minutes. If the V had the removable headshell it would really be easy.The removable headshell also allows for azimuth adjustment.
Jfrech--I also use a IV.Vi arm, but mine did not come with the damping trough. My trough was an add-on option which wasn't cheap. Maybe the 20/2 table comes complete with the trough, but I don't think that IV.Vi arms come with one.

Hi, In post above, I meant to say arm "cable" in my last paragraph.

"Not sure what arm you have right now. Also, if you have a 309 today (I am guessing here) have you tried better arm cables?"

WBS: you might be right, yes, my IV.Vi came on my SME 20/2 table. Sorry
Rccc - I currently own a Dynavector XX2 (Moving coil) - do you beleive it is a good match for either the 309 or an UP4 for my Avid Volvere?
Fernando, I dont have direct experience with that cartridge but it seems it should mate well with the sme. Im sure someone on agon must be running that combo though. post it as a general question.
Based on my research - I am leaning towards an SME 309 for replacing my RB300 on my Volvere - yes, the iV looks great - but out of my reach if I look for a mint piece.

Morch looks good - but I have found few owners with this combo - looks like the Avid is more in the liking of SME overall.

Origin Live are modified Regas - not sure if I will get the same level of improvement that with the 309.

Gooosshhh - this is hard!!