replacement of modified strut mounts

[Jvan]

My 94 has developed a knocking noise from the front drivers side suspension when going over bumps. After 200,000 miles, not a bad problem. Checking with the service bulletins on the forum, the TSB states that the problem can be solved by installing "modified strut mounts". Are these the same as "top hats"? Are there parts available from Group N or aftermarket that will fit the SVX? What are the "modified strut mounts" from Subaru compared to aftermarket, Group N, if these exist?