Ken I didn't even try the stock sender with the new VDO gauge. Didn't Mike just post that he did some testing on his stock vs. aftermarket gauge and it was the same? I know it wasn't a VDO gauge, but they often use the same senders.
The problem with the egauges sender kit is they don't have the proper threads to mount to the stock sender's location. They have a multi-sized kit, but it doesn't have the right size. I got mine at Autozone, it was a Sunpro sender kit... just like the VDO kit it contained many different thread sizes, but it had the *right* one.
I just checked egauges site... I think I got the sender from them, it's just the bushing kit I needed from Sunpro to adapt the sender to the stock temp sender mounting point thread size (listed as 5/8 18-UNF in FAQ).
I'm trying to remember, but I think I got the 250 degree sender with the 1/2-14 NPT size, and adapted from there... I think I called and asked for the 5/8-18 UNF, and was told to get a different one and find an adapter.