Nice progress and thankfully minimal rust! I have been wondering about that portion of the fender. In planning out some rust repair (my car was purchased in Chicago and lived most its life in WA state so it has some rust but hopefully manageable without crazy surgery) I followed the fender seam and it all of a sudden went smooth in that spot. Now I know what to expect when working on the fenders. 

I cut out the rust - shown above and below on backside. Not too bad.  Cut away minimal amount.  Now ready to fabricate two patches on the body and stay tuned for the fender work!

and here is the body shot

and for fun I took some pics as deep as I could into the rocker.   One is looking back towards rear and the other is looking straight down. Just surface rust.  I guess I treat that with some rust proofing jelly.  
 

I ordered the sheet metal for this section from W&N but I decided to fab it.  Will be posting that on eBay soon.  

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I finished up the right front - 

The fender came out great.  (I invested in a pinch roller to do that rib).  .040 4130 weldable sheetmetal.  

I did most of it with MIG and gave the TIG a go for the touchup.  This was my first time doing touch up successfully on the car with TIG.  A real pleasure.

The body also went well - I used .063 4130 weldable sheetmetal. This is the metal I cut out.  I have the W&N patch panel but decided I could fabricate this piece and get the job done - and though it is not how bmw did it - it came out really well.   

Welded it in...It was essentially a flat panel that extended to the fender mount rail.  

The backside with a fillet weld and ground down nicely.  

And some POR15 to cover it all up and show some needed touchup.  (you can see where I no longer have the seam where the fender mount rail joins the body - but to me it is OK.  And much stronger.  It is also simpler - I hated the thought of removing the fender rail when it had only 3 inches of rust along about 3/8 of an inch section.

And the W&N panel - I will post in classified.  Kind of interesting indent on it above the label - not sure what this is other than a feature added during the press process to hold the metal steady during stamping?  

Comments WELCOME!