A few thoughts.
- HD's stage 3 vs stage 4 torque profiles are nearly identical. The main difference of the stage 4 vs 3 is the 4's higher flow generating higher hp in higher rpms.
- if you want the best torque profile in a touring bike with an HD cam and you rarely ride above 3000 rpms, then the stock cam is your best bet. Forget about both the stage 3 or 4 kits if you ride below 3000 rpms since their advantage is above 3000 rpms
- Another thought is that with more timing advance and tuning with a Powervision plus a free flowing headpipe (warranty may be an issue), the lower end torque will be much improved in both Stage 3 & 4 kits without giving up the higher rpm hp.
The best torque profile I have seen so far was for the Woods M8-222 cam, I have seen the test's not for sale yet. With a good head pipe, mufflers, that cam and a tune it was a very good touring torque curve. Over 110 torque from 2250 RPM to 4500 RPM, with a peak of 121.64. Over 120 from 2750rpm to 3600rpm.
You pretty much sum up why I don't do HD kits, all I did was use their 117 cylinders on my 13 CVO King. Hwy cruising is right at 3000 RPM. Twisty mountain roads is 2500 to 4000 RPM. My CVO King is 120 torque by 2700rpm, 130 torque by 3200rpm and a peak torque of 140, and does not fall 135 torque until 5300rpm. Hp peak is only 138. Never have to down shift to pass, pulls like a train out of the curves on an uphill.