The box size and configuration will be determined by the parameters of the woofers. Period. You can't really force a woofer to work in the box you want to use just because it fits.
My long-term goal is a custom box, designed specifically for the drivers. I've been reading up on DIY speaker design plus I found an old catalog in the garage today, so I have all the specs I need.
For now I'll be chucking them in an old sub-bin, which I also had in the garage, while I'm building the real box. This is just temporary so I have sound in the meantime. For the final product I'll be going at whatever pace necessary to achieve the best results.
If you'll be using these in a car, you'll need a car audio amp. If you try ot use a home amp, you'll need a large inverter and that would be prohibitively expensive.
Any solid state amp will work into 8 ohms but the only way your amp will see 8 Ohms is if each channel drives one woofer. The amp's output rating is Watts, Load, % THD, 20Hz-20KHz +/- 3dB (or whatever they state), both channels driven. The amp itself won't generally be rated for output impedance so if, by " 8 ohm output" you mean into an 8 Ohm load, the amp will effectively see 1/2 of whatever the actual impedance is. The amp's design will determine whether it will work well into a 4 Ohm load and if it will, it will develop more power into a lower impedance load.
Car audio uses lower impedance loads because they take power from a 12VDC system. Kome equipment takes power from 120VAC/220VAC (possibly 220V in your case since "still in great nick" isn't a common expression here in the US) and is then reduced for the amplifier's demands.
240 is what we get here in oz.
Does that mean if I run the drivers at 4 ohms it'll draw extra power from my car therefore I may require a second battery?
How will changing the resistance/impedance on the drivers affect their performance? I understand if you wire the drivers up in a series, increasing the resistance, they will draw less power from the amp, and vice-versa with parallel wiring. But what does this actually mean? Is one way better than the other for the drivers/amp?
It seems like the way to go is running the speakers at 8 ohms, what they were designed for, and powering them with a 2 channel amp - 1 channel for each driver.
FYI- You bridge an amp, not speakers. You wire speakers in parallel or series. If you do bridge the amp, the current demands will determine the need for a second battery. If you add a battery and the amp draws enough current, you'll also need to use a higher output alternator, heavier charging lead and a heavier ground wire from the body to the battery.
Sounds like I should go for a 2 channel amp, no bridging, and run the drivers on 2 separate channels. Should I be looking for an amp with double the wattage rating of the (8 ohm) drivers, seeing as car amps are normally used to powering 4 ohm speakers? There are so many brands and models out there, I have no idea what I should be looking.
I might just google 'buying car amps' and see what I can learn.
I'll also be running 2 piezo tweeters along with the drivers (35 volt RMS, 100w amp power). <--- I assume this means it can handle 100w max. I don't think I've ever heard of tweeters
needing 100w to power them.
Many years ago I was told it's better to use an amp with a slightly higher wattage rating than the drivers you're planning to power, while running an amp with a lower rating can put a 'dirty signal' into the drivers if cranked up too loud, damaging the speakers. However if the amp is too powerful and you over-crank you run the risk of blowing them.
You'll have to forgive me mate, it's late here and I'm getting drowsy. Plus I want to learn as much as I can so I know exactly what I'm doing.
Cheers