| In my 2001 mini one, I must have spent thousands on after market equipment.
In the front and back, we had infinity high end speakers. A JBL 1600w 10" sub powered with an Alpine monoblock amp, and the front and backs, with a 500w 4 chanel alpine amp.
The head unit was one of the sony ones, with the tray. It was all very nice. . . . But.!
Sub output was crap, so I moved to a 12" square kicker. This was ok, but lacked any sort of quality, plenty of thump tho. So we eventually changed to a 12inch DVC Rockford fosgate. This was the best, allowing plenty of thump and sound quality.
Only problem was, without putting loads and loads of sound deadening material on the car, your poor car will vibrate to pieces. And remember, putting all the dynamat etc will annoy your dealer if you eventually part ex the car for another one etc.
Plus, you really lose the boot with subs.
Anyway, what I am getting at . . . .
If you can fit the HK equipment, I would damn well look into it. It is as good as my aftermarket kit when it was at its best, plus it wont ruin your car. Only problem you will have is getting your head unit to give you the HK settings. What I would advise tho, is this. Get a nice 4 channel amp, like an alpine or rockford. Remember, You can get better sound out of a good amp with poor speakers than a crap amp with good ones. Try to get an amp with crossovers built in. Then attach that to the rear of one of the back seats. Mikeythemini will have some sort of cable to get an aux out of the original head unit (if you have a post 04 model boost, I think you will have mp3 capability)
Then get hold of the HK speakers, all round. Sometimes you can find these on ebay, but rare. Remember, when HK speakers were designed, the area volumes behind the speakers would have been taken into consideration, therefore they will be almost perfectly matched for your car.
Fit the speakers to the after market amp, and use the crossovers to limit the sub sound going to the rears. If you do this well, I think you will get a nice sound all over. Plus its not too hard to wire up. Easiest way to do this is to get a car audio company to fit some of it, but not all. I would not trust anyone with my car. Get them to fit some nice quality speaker cables to the ones already there behind the stereo, tell them to wire them to the boot, I say nice quality but dont go mad. There is no need for all this super thick oxygen free stuff. Then get them to fit an amp kit. Dont worry about power caps etc, your battery on its own will be fine. Then you can fit the speakers and get it raring in time for tea!!
Good Luck! | 
