Car Audio Help Needed!!! Need to know how many Watt Amps do I need for Sub-woofers?

[john]

I'm about to upgrade and put some a 10" sub-woofer in my '92 Ford Ranger Single Cab, but I need to know how big of an amp I need. Best buy has a Diesel Audio - 10" Dual-Voice-Coil 4-Ohm Subwoofer that handles 400W continuously and has a peak of 800W for like $30. It's one of the cheapest Subs they have, but its got a 4 1/2 star rating so I don't think it'd be too bad. I just wanna know this:
1. Are there any other cheaper/Better subs out there?
2. What is the general rule for how big of an amp you would need for different size woofers?
3. Is it better to spend money on the pre-made woofer boxes? Or is it okay to just make one? Which I can do, but is there some special effect that the pre-made ones have other than having auto carpet on them that I can't make?
Thanks for your help

 

[TaylorMorrison]

Alright first off the sub is probably not amazing plus it states 400WRMS but probably only handles about 300 however don't assume this and always find an amp to match, mono block amplifiers are designed for subwoofers they have a single output either at 2 or 4 ohms so find a mono block amp with 400 RMS such as a Pioneer D class 7500 it does 400WRMS @ 2 ohms so it is perfect

Secondly when it comes to an enclosure if you havent done much car audio before then i suggest buying a pre made sub box they are built generally to about either .77cuft or 1.25 cu ft which is perfect for any standard 12" or 10" subwoofer however if you know enough about it and perhaps want to build a custom shape or design feel free but make sure if it is a sealed enclosure then be completely 100% certain that IT IS SEALED, if a ported ( try to avoid they are terrible) check what size port will suit the tuning of your sub so most common is about 7" either slot or trumpet
and they are mostly tuned to around 60Hz so try and match that