To Bill Gum, Yes you can bore the sleeves that are in your car for oversize pistons. Lord knows how many I have bored for oversize pistons. If you couldn't, why do you think Mahle would make them. Yes, Mahle makes the pistons used in Mercedes.Make sure the 1st oversize will do the job.0.25mm is not much, something like 0.010in. I have even bored gasolene engines for oversize, and they don't have sleeves.
Keep us posted on you progress.
Bill Lewallen Lexington,Ky.