The DR200 uses an eight and has average sensitivity of 105dB/1watt; the DR250a uses a ten and SPL is 107dB/watt. The DR250a will handle a bit more power as well, so total output capability is about 130dB with 200 watts in, while the DR200 will put out about 127dB with 150 watts in. The main difference is size and bandwidth; the DR200 is useable to about 70 Hz, the DR250a about 50 Hz. If you want to run bass instruments without having to use a separate sub you need the DR250a. If you don't need the capability for handling bass instruments, or if you plan on separate subs anyway and want the smallest package, go with DR200.