It not an economical solution. The appeal of the B200 is its increased metal between the cylinders for high boost applications or if you live in the UK the tax purposes. Boring it out will just give you a plain jane B230 that costs you more and introduces more possibility of failure as you will be required to get new matching pistons, rods and possibly crank.
If this is your first time doing a turbo build then start with either a late model B230 or B230FT. This will be the most cost effective and simple solution that will still give you a great start in the world of wrenching. By all means hold onto the B200 but take a look at what it might take to turn it into a B204GT which would be an interesting and potent little motor.
Heres some reading on the different types of redblocks you can encounter.
https://en.wikipedia.org/wiki/Volvo_Redblock_Engine#16_Valve_Variants