I recently changed the spark plugs, coils and wires with exactly the same oem ones. Reason for change was cylinder 3 misfire due to cracked coil, so I decided to do the whole shebang. Now the car is running noisy/bassy. It also stutters a bit during rapid acceleration...it might be a vacuum leak but the carburator spray around vlconnectors test came out negative (no change in rpm from idle). The muffler seems ok. The only thing is that when my wife took it to the dealer to have the oil done, the dealer said that the engine mounts are worn and require replacing ($700). As a side note, how important are engine mounts?
Post a picture of the carburettor of that vehicle and I am all too eager to help.
Engine mounts are fairly important if one does not want the engine to spin within the engine bay or collapse to the lowest level of support. Also, they keep the entire drive line in alignment. It is possible to have the mounts collapse and have hard contact with the body or frame and resonate through the body causing the noise you are now hearing.
I remember working on 70s era Volvos that had D-Jet, then came L and K. I don't think Volvos were carburetted at all past 1979.
To the OP: Why don't you call other shops in the area and see how the price compares? Bear in mind if you have the dealership replace the mounts you will be getting OE Volvo mounts, on the independent side the mounts will likely be aftermarket replacements which may be equivalent enough to the OE to be acceptable and probably less cost than the OE.