Title says it all. Has anyone replaced the horn with something more substantial?

You can get the hella horns

https://www.ecstuning.com/b-hella-pa...003399801~hla/

Checking this kit out... looking at the website order, note that once I plug in my car make/year/model there's a notice that it is "Not plug and play. Will require modification to install."
Does everything needed come with the kit? Are there installation instructions shipped with the kit? TIA.

yep its universal.

On an R53

Great! Thank you!

Welcome.