Haha cool.
What car you got mate?
Normally two twelves or one fifteen is about ya limit for a boot. But obviously dome boots are bigger.
I'm stabbing in the dark here as we don't know what car but same principles apply.
Most car batts are around 50-70ah. If you only want one battery you'll need to upgrade it to a decent 100ah ish (only reason I say that size is that'll probably be the biggest you can fit in the engine bay).
Alternator wise. If you want any decent power this'll need to be upgraded. 150-210a would be good.
When you figure out what alternator and battery your going to be running you can decide on power. For instance (and this is totally "just my opinion")
95ah batt, 180a alt. 2.5-3k very max. This will allow you to "showoff" for short periods of time. This will also be very loud with two twelves or one fifteen.
65ah batt, 90a alt. 1-1.5k I'd say. This will still be quite loud but tbh lots of people run this power do won't be as impressive for "showing off".
Where are you based? Your more than welcome to come have a listen/play of mine mate. Different people have different ideas of loud. Mines nit loud enough for me, but only a hand full of people will sit in it when I turn it up.
It'll also give you a better idea of how power supple affects your install as I haven't got my alts in and have taken the 3 extra batteries out.
