Uhmmm, it's almost like the internet is not filled with threads that all the 83mm blocks will crack the sleeves above ~250hp or a bit more. No matter...what your tune is. Just look at factory S60R with no tunes.
You need to shim the block OR install Darton sleeves. 2.3T is a good choice, if you can, also shim that one, just in case. But those can hold 400+ hp without shim. But if you will swap heads, just shim it and be ready for 500+.
Always knew about weak points of this engines, but somehow gave a chance and hoped that it will last longer than 2 years and FYI my 2.5 block was shimmed. One of the problem was that i didn't check tune in the first place when bought car, but on the other hand in my country nobody wanted to tune volvo, everybody only knows how to deal with bmw's and vag's. So after I cracked sleeve I started digging and found this forum so with new engine will try to tune it myself.
Talking about new engine the block is already shimmed along with h-profile rods throwed in, just waitin for few other parts. Power goals are in the range of 400-450hp.
And in between shims or darton i also can put another mod...CLOSEDECK. Already tested on friends 650hp build, holds power flawlessly and is cheaper than installing dartons.