Originally posted by suginami
You can always replace the valve seals with the head on, but you can only replace the valve guides with the head off.
Since you have to remove the head to replace the gasket, spend the extra $200 or so and replace the guides and seals.
You'll then be good for another 250,000 miles. The new guides and seals are better than the originals.
This is good advice. Don't spend all the money to have the head pulled and put it back on with original guise/seals. Spend the extra for a good top-end job. Also, the 190E 2.6 engine has a single row timing chain that lasts a long time thanks to it's short path, but budget allowing you might want to pop in a new chain/tensioner too.
Our 190E 2.6 has just shy of 200K-miles on 'er, and the top hasn't been off. Are you sure the head gasket is leaking? Much more common on the M104 DOHC engine...