As you probably know, I finished the 110->617a swap a couple weeks ago.  I had both factory and "1" forward" mounts in my hands during the swap and made the choice on the spot.

The only bummer with moving the engine forward an inch is that you don't just need to change the engine mounts, you need to change, or at least manage the effect on,  EVERY connection between the engine and rest of vehicle.  Drive shaft, throttle linkage, oil cooler lines, fuel lines, coolant hoses, shifter linkages, clutch slave line, etc.   In practicality, this usally just means a 1" thick drive shaft spacer "donut" on the transmission output flange, but even that can be non-trivial if the transmission you have does not have sufficeient space between trans case and flange to allow fitting longer bolts through the trans flange without removing it. (4speed amnual doesn't allow, I HEAR the auto box does)

That said, moving the engine forward also positively effects a couple things besides the oil pan.  It gives a little more room between the head/valvecover and the heater plenum/bulkhead.  This is handy when pulling hte valve cover for valve adjustments, and when changing the heater hose, if you've changed the water exit to the rear as I did (no difference if you leave water exit on side per factory).  It also gives a littel more room between the turbo outlet and the bulkhead, giving a little more freedom in when to make the down-turn with the exhaust.  Both of these fit into the "nice to have" category, however and are not at all necessary or even hardly noticeable, whichever way you go.

The biggest input I can make to you considering having mounts made is to be sure they can be made in a precision manner that results in the ONLY difference from factory being the 1" forward motion.  The reason I ultimately decided NOT to use the 1" forward mounts I had was that they just were not precision made.  They would have needed more shimming with washers or other stuff to get the engine sitting level side to side, and in the right spot vertically.  They were slotted where the mount bolts went through, not nice tight holes like I would have liked.  The ones I had also didn't accurately duplicate the angle where the engine bracket contacts the mount and would have needed some grinding or filing depending on where theengine ultimately ended up.  Bottom line, they just weren't made up to the standards I wanted.  In hindsight, I think that if they HAD been made to be a precision fit and to move the engine just 1" forward keeping all other things equal, I would have used them.  But in the end I chose to go with the factory mounts.

All the other stuff in the thread pertains to the factory mounts and I can't say too much more about those.  When Dai talks about them being much better than the sedan mounts, I don't know.  The pre-82 GD engine arms were forged alloy and they seem plenty strong to me.  I'ce never heard of failing engine mounts in a G of any vintage.  But I do know that MB changed the engine mounts in '82 on G-wagens for a reason, and their reasons for doing such things were ususally good.  Your post-82 trapezoidal mounts are probably better and longer lived than the early style rubber donut type (which I have), and you're probably not concerned with any "NLA" issues with the trapezoidal mounts.  I had originally wanted to convert to the trapezoidal types until I found out it required cutting off and welding new parts to the chassis.  One reason I went with the MB diesel engine was to avoid that kind of thing.  So I'm in with the 300GD alloy arms and rubber donuts and was able to buy all the parts new when I wanted them, but that was a year+ ago.

Anyway, I'm rambling, but I think that about summarizes the issues I saw.  I put mine in with the factory mounts, I use 2-stripe white springs, which effects the engine/axle relationship a little, but I haven't modified the oil pan yet.  I'll probably do something with it, or the axle bump stops, or both, before any off-raoding next year, but for on-road driving, I don't have any issues with clearance.

All the best,

-Dave G.