The hot start problem stems from an engine with very tight tolerances, a too-small starter cable wire gauge, and a barely-adequate gel battery.
You have several options:
1) Ride it as is, and get annoyed every so often.
2) Continue to push BMW for a solution, which they may or may not do under warranty.
3) Find the part number for the new battery cable and order and replace it yourself.
4) Investigate the newer LiPo batteries which are smaller and lighter in weight.
5) Just buy an Odyssey PC680 battery like the rest of us and never have this issue again.
On the PC680, the standard battery is fine; the Metal Jacket version isn't strictly required. I went with the MJ because the price was close and I wanted a bit of extra heat protection, and the battery sits right above the hot engine. Check around locally and online to get the best deal you can, including tax and shipping.
Then just go out for a nice, long ride . . .
'13 Dark Graphite Metallic K16GTLD, 24K miles and counting...
'09 Magnesium Beige Metallic K13GT, 60K miles miles and counting...
'02 Mauve Metallic K12LTC, 106K miles and sold
BMWLT#145, IBA# 366, MOA# 111996, SCMA# 24032
All lower 48 states plus Alaska on the K13GT in two weeks . . .
Some people see the gas tank as half empty. Some see it as half full. All I care is that I know where the next tankful is coming from...