HI, Glad you got one of the beasts. Isn't it something? I think that one of the main differences between the two /85 kits is that the #174 has a little bulge, so to speak, in the side of the turret. At the moment I can't remember what exactly this is for, radio or turret transverse box, or some such thing. Too bad that Trumpeter didn't use one of these two /85 kits to produce one of SU models for this tank. But I guess we can't have everything.
I have the #174 out in the garage sitting patiently in the box, gathering a fair amount of primer dust and other assorted items. After having done both the '43 and trying to finish up the '42, I'm kind of 'burned out' on them at the moment. Besides since I do my work in an unheated garage, good old Mother Nature has stopped any kind of work out there on anything big for the time being, other than a quick rush out with the primer to paint something. Have been regulated to a small TV tray in the corner of my bedroom till spring rolls around. I'm also watching the build going on over on tanxheaven and taking notes off of it on the instructions of the #174. I think that the /85 kit is going to be one of the best of the lot, mainly because of those little differences here and there compared to the other two earlier models of this vehicle, which are basically the same except for the turrets.
As far as 'accuracies' goes I think that this just depends on the modeler more than the kit, as all kits do have their flaws about them and it's up to the modeler to either correct them, or to live with them, as they so choose. Probably the models of the earlier vehicles would have the most 'flaws' to them, as I heard that this kit is designed off of an /85, so there are some things that didn't exist on the earlier vehicles that show up in all these kits. (As an example, the two side panels in the fighting compartment are 'dented in' for the additional size of the /85's turret, and they were straight across for the earlier /76's. But unfortunately all 4 kits have this indentation in them. I didn't know this when I built the /43, but corrected it as I built the /42.)
Personally I think all the kits are really great! And with all the new information coming out all the time about this vehicle there are all kinds of changes or modifications you can do if you wish to make things just a tad better here and there as you go along.
Personally I'm planning to replace the mg's position in the hull of the /85 with the flame thrower tank and gun unit to add something 'new' to this particular kit.
Good luck and take care, Sgirty