This might be a little silly to post in here but I think it is a major upgrade.
I grew tired of the "moped" horn on my xB, so I started hunting a replacement. Decent aftermarket horns were in the $30-$50 per pair range, so I visited a local salvage company that specializes in disassembling very new imports. 10 bucks later, I was the proud owner of a pair of Fiam horns from a Mazda 6 that looked like brand new.
I had to mount them more to the center behind the grill due to their larger size but was able to use existing holes, bolts, and even brackets. The sound is incredible and LOUD! The new horns actually pull less amperage than the OEM horns, so using the same horn wiring was not a problem. Once it was all buttoned up, nothing is visible at all. Cheap and very effective mod... I love it!
If you should decide to do this, all you need is two horns with about 6 inches of their plug and wiring, two male spade connectors, two wire ties, and about 30 minutes. Make sure you get single wire horns and that they are fairly small. Honda Accord and Mazda 6 are good sources. I sourced a low and high note horn so the tone had a nice sound. Although the spade connector will plug into the factory plug, I recommend using good electrical tape on the connections just to make sure there isn't a chance of them coming unplugged. No wiring was cut for this installation.

The blue tape is just there to keep my grille from scratching the bumper when removing and reassembling.
