Jorsan, I am aware of the recommendation, but you realize that VPI's recommendation is to use the cartridge outside of the cartridge manufacturer's recommended range. Let's look at this advice for a second. At first, it seems quite benign, you are only using the cartridge .1 gram over the maximum. I believe that this translates to only 3.6% over the maximum recommendation or 14.3% above the recommended force of 2.5 grams. Of course, there are obvious consequences to increasing tracking force, diminished stylus life, increased record wear and accelerated wear of the suspension. And I have no doubt, that these increases may be moderate in the context of a properly aligned system. Then again, by going past the manufacturer's recommendation you may be moving the coil out of the linear part of the magnetic gap. So, in addition to putting added stress on the mechanical damping system, you may no longer have optimal electro-magnetic damping of the moving system, as well. What other precision products would you use outside of the maximum recommendation from the manufacturer?
Personal experience using unipivot arms - and I hasten to add, not the JMW - that have no anti-skate - the Grace 704 and 714 as well as messing around with two other unipivots that I have owned, the Morch UP-4 and Audiocraft (Ultracraft) AC-300, without anti-skate, I can tell you that there is no need to increase tracking force to properly track highly modulated inner grooves without bias compensation. At least if the arm is correctly designed, and the effective mass and compliance are correctly managed.
There also seems to be some confusion about what constitues low, or high, effective mass in a tonearm. The JMW is in the range of 9 grams effective mass, without the auxilliary weight, which puts it within a hair of the Rega RB-300 as far as effective mass is concerned. Call it low, call it high, but it is much lower than the broadcast arms that the 103 was designed for, which generally exceeded 20 grams of effective mass. And, as a previous poster pointed out, the 5cu spec that Denon publishes is non-standard and implies that the compliance is lower than it actually is, but even at 12cu, this is a very low compliance cartridge. Denon even made a consumer version of the cartridge, the 103D, to address just this issue. It is considerably higher in complinace than the 103 and still is not a particularly good match to arms in the 9 gram range. The Zu 103 is specifically designed on the RB-300, which is why they add so much mass, in addition to the increase in rigidity. The TWL mod is a simiar attempt to increase arm mass to match lower compliance cartridges.
In the end, it comes down to a matter of how each of us hears. I purchased a Denon 103D new in the 1970s and a 103 sometime thereafter. I have used them in over twenty arms, and my personal observational experience is that they will track in pretty much anything, but they will not begin to sound their best until you are over 14 grams of effective mass, and they will not produce the full color that they are capable of until they are used in arms over 21 grams of effective mass. Your mileage may vary, and probably will. Again, if it sounds good to you, then it is good.
Personal experience using unipivot arms - and I hasten to add, not the JMW - that have no anti-skate - the Grace 704 and 714 as well as messing around with two other unipivots that I have owned, the Morch UP-4 and Audiocraft (Ultracraft) AC-300, without anti-skate, I can tell you that there is no need to increase tracking force to properly track highly modulated inner grooves without bias compensation. At least if the arm is correctly designed, and the effective mass and compliance are correctly managed.
There also seems to be some confusion about what constitues low, or high, effective mass in a tonearm. The JMW is in the range of 9 grams effective mass, without the auxilliary weight, which puts it within a hair of the Rega RB-300 as far as effective mass is concerned. Call it low, call it high, but it is much lower than the broadcast arms that the 103 was designed for, which generally exceeded 20 grams of effective mass. And, as a previous poster pointed out, the 5cu spec that Denon publishes is non-standard and implies that the compliance is lower than it actually is, but even at 12cu, this is a very low compliance cartridge. Denon even made a consumer version of the cartridge, the 103D, to address just this issue. It is considerably higher in complinace than the 103 and still is not a particularly good match to arms in the 9 gram range. The Zu 103 is specifically designed on the RB-300, which is why they add so much mass, in addition to the increase in rigidity. The TWL mod is a simiar attempt to increase arm mass to match lower compliance cartridges.
In the end, it comes down to a matter of how each of us hears. I purchased a Denon 103D new in the 1970s and a 103 sometime thereafter. I have used them in over twenty arms, and my personal observational experience is that they will track in pretty much anything, but they will not begin to sound their best until you are over 14 grams of effective mass, and they will not produce the full color that they are capable of until they are used in arms over 21 grams of effective mass. Your mileage may vary, and probably will. Again, if it sounds good to you, then it is good.