Yeah, I agree with the former posters: if your really planning on turbo in the future, try keeping the barrels as thick as possible. Most important therefore is to go look and measure up the old barrels if they are still round enough and if they will support a set of new 94mm pistons.
The cool thing about forged pistons is, that they will usually be made too big in diameter, so you can have your barrels be honed out a bit more till your on the right spec for wall-piston clearence
Then again, I believe there are also 95mm forged AA pistons now and that +1.0mm will cover all rust and scratches you may have encountered with old barrels.
New 'B' Mahle pistons are not readily available at the moment iirc, so make a plan. Maybe the true forged 94mm AA's are worth a look?
Boring and honing is usually just as costly as all new barrels and pistons, though the original barrels are _usually_ indeed better then new these days.
In short: your choice in pistons and cylinders is very important in a build like this.