Whats the miles on that 240D???

Instead of going to tranny shop, why dont you take the head to machine shop that can also wiggle the valves in their guides to check for excessive play and measure the head for warpage, spotting tiny cracks or anything else that might be wrong with it.

But whatever you do - dont let em shave or plane the head beyond MB specs, if at all... this can bump the compression beyond tolerances and soon blow the engine if they remove too much metal from surface area.

On cleaning surface contact areas of both head and block I've always used 220 grit sandpaper.... i dunno about steel brush wheel. I think valve guide seals come with the complete head gasket kit, so you might as well have the shop install them too.

Better let the machine shop itself order whatever guides you are haggling with Phil about... they come in standard size and oversize that can only be measured with machine shop calipres to fit worn valve stems.

Damned easy... pulling the cyl head on 240D, isnt it? And dont forget new manifold locknuts when you get back to Phil.