Lumpy (originally) is the nickname for the TM Ultimate Driving Iron.
An actual UDI #3 is 38.75" long, and has 20° loft, not 21°. How much different will it be than your E8 4i (38.75" long and 21° loft)?
The E8 irons have heel-and-toe tungsten weights, so the 4i should get the ball up well.
You're a 10.1 HDCP, so your swing characteristics might give you some clues. If you have a quick transition, the driving iron might give you benefits over a 4i. You would have to do a side-by-side to tell whether to go UDI/DI or keep the 4i.
The 7W would get the ball out of medium rough quite well, and would give higher trajectory than a UDI/DI.
Caution on adding a fifth wedge: If you're a Pelz-style mechanic on your partial wedges, a five-wedge mix might be extremely hard to manage.
I am liking the feel of the lead leg folding in while the back leg straightens.It seems easier to keep the head steady and there is a certain feel of power.I think that is why I also like the inside path takeaway which is my natural tendency anyway,it feels powerful.