Only upgrades to a D35 that matter..
30 Spline larger shafts in Chromoly over the 1541 27 spline stock stuff. He much think that a 30 spline dana 35 is just as strong as a 30 spline D44 and the chromoly over the stock D44 1541 material, make the D35 stronger then?
Wrong. The D35 is smaller tube, and much smaller ring gear and the pinion head and contact area are much smaller then a D44. Not to mention the larger pinion bearings, and carrier bearings of a D44 are bigger. And the axle bearings are larger in the D44. Yes the dana 35 30 spline still has C-Clips, but thats not really a down side anymore, since you wont break a shaft anymore.
as for lunch box lockers. In a stock 27 spline dana 35 they are Junk. D35's are typically bent, a huge no no for a insert locker. The shafts are weak also in a stock dana 35. and the insert is very shock loading and typically helps break a shaft. Think of it this way... Take a glass table, slowly lower 100lbs of wieght on to the center of the glass. It holds it. Then take a metal key or such, and tap firmly on the glass near that wieght. Shatter... Same typ thing with a insert and a dana 35. its at its limits with a 33" tire to start, then start shock loading it.
Do the D44 if you have it. And a insert locker in that axle is more suitable, but a full case locker is always better....