I have had an SME V in my system for numerous years now. I have modified it in the following ways:
1. changed external wiring first to Cardus and then to Siltech Avondale;
2. changed internal wiring first to Van den Hul MCS 150, and then to Kondo;
3. removed the bridge;
4. applied very small amounts of damping material (in fact a sort of adhesive putty very similar to Blutack) externally to the armtube at certain key points (near the bearings, near the headshell).
When the arm was sent to SME for the second rewiring it was already without the bridge. SME did the job without demur and returned the arm without replacing the bridge. On the phone they said that they had seen a number of arms modified in this way (they simply warned me to take care - should I one day decide to replace the bridge - not to tighten the screws too firmly : apparently this could damage the bearings).
The following well-known modification I decided to forego:
5. bypassing the headshell clips and running a single length of internal wiring from the cartridge clips to the five pin connector in the base.
I abandoned this idea on advice from SME and others (Definitive Audio, UK): the more delicate the internal wiring, the greater the likelihood of breaking one of the strands while changing cartridges.
The application of the damping material was done on the basis of advice received in this forum (Dertonarm, who I thank). There are also posts on Vinyl Asylum that recommend this. I experimented quite a bit, varying the amount of the material and the position. I ended up rolling it out in order to reduce the thickness and obtain the best extension for a given weight of material (I doubt if the total amount I used was greater than a small pea). Once applied it can easily be coloured with a black felt-tip pen, thus reducing (but not completely masking) the undesirable aesthetic impact. Of course, downforce has to be adjusted after application.
The more recent of the above modifications - the change to Kondo internal wiring, the removal of the bridge and the application of external damping - have all (in my opinion) contributed to increase the neutrality of the arm. The playback I am getting now is more relaxed, more airy and richer in tone colours and in spatial definition than it was before (cartridge: Benz Ruby II, retipped and modified by Roberto Torlai. Turntable: SME 30/2).
Best wishes.