Frank, in many parts of the world, DHL is the preferred shipping company but DHL couldn't compete here in the states so they basically closed up operation except for their express mail divisions. But DHL has a delivery agreement with the USPS so our local post office will deliver DHL shipments here in the states. What you should try to do is spend some time and be a little more thrifty on carton sizes. Even a few inches either way will make a huge differences.
Basically, if you can cut your dimensions (length + girth) to under 108", then you qualify for the lower rates. Once you go above 108", up to a maximum of 130", the cost climbs astronomically. Over 130" and it's not shippable via the post office. Some destination countries also can't ship anything above the 108" L+G and some can't even go above 60".
For example, I just checked at USPS and 25lbs. to Germany with a Box 32 x 22 x 16 is $82.17 for priority, $113.02 for express, and $320.94 for global express. I understand that it might be a smaller box than you feel comfortable with but given the choice between $900 and a little more protection, and $82.17 and less protection -- I might be inclined to accept the greater risk of the smaller box, but maybe bolster the corners with metal, wood, more cardboard, or other such creative methods. It takes more work to "make" a perfect box. But the cost difference warrants the extra effort needed to keep costs reasonable. Most boomboxes can fit in a 32x22x16 carton unless..... are you shipping a C100 or Wheely, or J1, or VZ?