sub questions?

[L33SMK]

Is nominal power handeling, just like RMS?

and if a sub is 3000 watt for example what input power or (amp power in watts) would i need?

chears.

[Predator_R32]

nominal will be the rms mate, dont take note of the max power ratings, just the RMS/nominal/continuos

[Noddy]

Ideally, the RMS rating of the AMP would match or be slightly less than (but not more than) the RMS rating of the speaker that its driving :) ??

[L33SMK]

Thanks for your help!

[CSVTR]

Ideally, the RMS rating of the AMP would match or be slightly less than (but not more than) the RMS rating of the speaker that its driving

Far from true i'm afraid, speakers can comfortably handle more than their rated power if the amp is set up correctly.

Power ratings, where they are realistic, are based on a 0dB tone played evenly at that power. Most recordings are at a lower rating than 0dB, so you lose some balance between the rating and actual output from that. Then consider the fact that music plays at varying levels (very rarely maximum*) the power levels are reduced further. Then add in the fact that more often than not the gains are set at around 75% of max, and power reduces further. The end result is that the real output of an amp could be as little as 25% of the rated RMS power, although 50% is more likely in decent kit.

If you get an amp that delivers around 50% more than what your speakers are rated at should be fine, just go easy on the gain setting on the amp, don't go whacking it up to 100%.