Product review (5 stars): Exact replacement, easy to do with just two tools.
Exact replacement part for the Bosch oven igniter, Bosch range model HGS5052UC01

I was able to quickly replace this part with just two tools:
- Phillips head screwdriver
- T10 torx driver (for the two screws holding the igniter to the top gas pipe)

You *will* need to open the back of your range to replace this, top or bottom. I was replacing the top/broiler igniter.
Compared to my bottom igniter (many years old) this thing is like lighting a match in how quickly it gets up to operating temp.

1) Unplug range, turn off gas, pull range out so you can access the back panel easily

2) Remove range door (two little flip-forward pieces on the hinges allow removal), oven shelves

3) Place towels over bottom of oven so you don't lose any screws in there

4) Remove 4 screws holding the rear panel in place (you won't remove it completely, just enough to get access)

5) Unplug insulated wires feeding in from the top, making note of which is which (one has a label attached - going to the black wire in my case)

6) Remove 7 screws holding upper assembly in place (including 2 holding a plate against the rear of the oven interior @ the gas feed)

7) Pull burner assembly straight out

8) Remove igniter from burner assembly (2 x T10 screws with lock nuts on bottom) and replace with new igniter

9) Feed wires through hole and secure burner assembly in reverse order of removal, insuring the gas pipe is a good connection

10) Reconnect wires in the back of the oven, again making sure to get the right wires to the right connection

11) Replace 4 screws holding on back of oven

12) Reconnect power and turn on gas and listen/smell for any leaks

13) Test. It should glow bright red VERY quickly and the broiler should ignite.

14) Enjoy your now-working oven.