This is amp is fantastic reasonable size compared to power, and if it's not going to fit on the side of the boot ( like I did) then you can always take of the end caps that protect the wires.
These ratings are RMS 4 ohm
4 x 100 watts
2 x 325 watts
2 0hm is 160 watts.
It's got everything you want on it like gain control, bass boost (0,12,24 db) High pass and low pass filters
The Good thing is that every option above can be seperatly adjusted to each 1/2 channels and 3/4 channels
So this amp is good if you just want it to power 4 speakers. Good if you want it for a sub or two .
Because theres seperate settings for the front and back channels it's perfect for using as a 3 channel amp. Thats 2x100 watts for speakers and 325 watts for a sub ( thats all 4 ohm) but I believe you can have different ohms on channel 1 and 2 to 3 and 4