upgrade from 3.1.3 to 4.1 and still keep unlock with bootloader 5.08?

[bisache]

I have a 3g currently at 3.1.3 jailbroken/unlocked. My BB is 5.13.04 which was downgrade from 5.14.02 via fuzzyband and a bootloader of 5.08. I was on 4.1 couple of days ago and then found out about fuzzyband and how to downgrade my BB. I want to know a couple of things, Can I upgrade via pwnage tool or snowbreeze and still keep my unlock? Is there a way to keep all the apps/cydia apps and themes that I put on the phone already or do I have to start all over? Will upgrading change my bootloader or is your bootloader always the same no matter how many times you upgrade? If all the stuff above is dueable, can you just give a simplified ordered list of what I have to do to achieve this.

Thanks in advance

[iYeow]

Yes, you can restore to custom firmware to preserve your baseband.
You can use Pkgbackup to back up your stuffs and restore back again.
Some themes that works on 3.1.3 may not work at 4.1, just to let you be aware.
Your bootloader will not change.