Ken I have a 454 engine in my Bounder....Never played with the air intake. I use the stock plug AC Delco plug. I place about 2000 miles on my rig per year...it just did not make much sense to go expensive plug. Buy ACDelco Spark Plug CR43TS at Advance Auto Parts
Sway bars.... i have performed a sway bar upgrade and love the results. I did two parts....front and rear. I did the work myself. The HElwig 1 5/8" anti sway bars on my front end with a Henderson Super Steer Tru Trac for the rear. The combo gave me a really super handling rig. Even though I drive an older 34 footer.... I was being blown all over the road by other trucks and some cars passing. Not anylonger.... the upgrades gave me a sweet straight tracking ride that I can now relax my arms when I drive.