Advice on horn relay / wiring

[mtj2k]

So one of my horns gave up - the low tone one - my golf sounded more like a golf cart! I decided to replace it with a slightly better horn - a Stebel Nautilus Compact.

No i removed the working horn - fitted some spade connectors into one side and mounted the new one.

It works - but not as loud as i thought it would (149Db). So here are my questions:

Would fitting an additional 30A relay make any difference to volume/response time?
I know the car already has a horn relay (J4 IIRC) - can i upgrade that instead?
If i do install a relay - do i wire it to the battery or to the fuse box?

Thanks in advance - 

[Jacker]

Just be careful doing this as the aftermarket horn may draw more power to work, the cable may not be capable of delivering the required power.

Easiest way would be to Wire a new fuse in the fusebox (or an inline fuse from the battery to relay) then take the relay control feed from the original relay to the new relay that switches the power to the horn.

Just make sure you have a Big enough cable to cope with the power.