zibbytbo: How goes it?
Well it sounds like you are getting an Idea.
I will only say this once and then we go back to the direction you are heading... I would go computer based. The editing ability is har to beat. You could play the chorus good once and copy it and use it for all choruses. etc, etc. It would cost you a few bucks though. You may want to make a shopping list going each way and compare what you are getting for your money. I know for alot of people wha have not tried it the prospect of using a computer to record seems like it would be a pain in the ass to learn, It is, but the boss unit is a computer and I bet it will be a pain in ass to learn as well only it will be far less adaptable.
OK I'm done.
It looks like with this unit you would at least need one preamp to record two vocal tracks at the same time. The unit says it has 1 built in. You will need two condensor mics (well if I was you I'd record one vocal track at a time). Maybe
the MXL v67g or
the Audio-technica AT-3035 or the studio projects c-1 would be good quality starters. You can go cheaper with the mics. You could get a couple of
MXL 990's or studio projects b-1's. If vocals are your focus I'd say you will drop $300.00 or more for a OK Pre amp, by my standards at least (some would say $2000.00)
You will need a dynamic mic for guitar. I'd go with a SM-57. You will need to mic the bass (you could use the 57) or what most prefer to do is run it direct in which means you need a DI (direct) box. The favorites on the direct box seem to be the Sans amp and the country man. You need some decent head phones to play or sing along with. You will need a compressor if you ever hope to achive studio sound (this unit may have compression).
Well thats a starter list. Figure on $200.00 or more in cables also.
Oh ya to ever mix good you will need monitor speakers (this is a must) You could get a amp/speaker combo that will get you by for about $350.00 to $500.00 dollars. You might look at the Tannoy Proto-J (speakers) and Hafler TA-1100 amp Combo
Well I would write more but I need to go. Think about the computer. You may need the unit to be mobile and in that case I'd agree go all in wonder. If not I would really think about it.
Good luck
I'll be back

F.S.