Since DC++ is developed under GNU/GPL, you can download source and modify it.

Features:

• Safe segmented downloading - Download one file from more users simultaneously without corruption! This way of downloading can dramatically improve download speed, especially for fast connections. Segment position ans size are decided by file size and download speed
• Partial file sharing - Allow downloading and uploading parts of file which is being currently downloaded by you or other users. This increases download speed and file expanding over network.
• Download/Upload speed limiter - Avoids a full line usage to leave some speed for web browsing. Realise, that download speed limit is dependent on upload speed limit which is dependent on amount of opened slots/hubs.
• Automatic slow downloads disconnecting - Disconnect sources which speed is under certain value for certain time. If download speed during segmented downloading goes too low, the source is disconnected regardless the set value to avoid unnecessary slot usage.
• Customization - You can set sounds according to situation, change color scheme or icons, show popup balloons, see emoticons and many more...