<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">if they are worth it? </div></BLOCKQUOTE>
If they were of any benefit, the engine manufacturers would include them to reduce warranty costs.
I believe it's another solution to a non existent problem.
Adios, Dirk - '84 Real Lite Truck Camper, '86 Wilderness Cimarron TT, previously 4 years as a fulltimer in a '07 DSDP