92-93 Deville, Gas

anyone have a 92 or 93 with a 4.9 and run it on regular? im looking to buy one, but kind of nervous about having to use mid-hi grade. is there an additive i can use instead of the higher priced gas.

Also were there any these models made without the auto leveling suspension?

the additive is 5 bucks and boosts it up maybe 2 octane points, and works only one tank. i mean seriously save the 3 bucks and fill up with premium, much better value.