318I vs 318IS

[vmckague]

What are the differences between the 318I and the 318IS? I have a 92 318I convertible and so for I have added the IS front lip spoiler, rear wing and side skirts. My motors manual showes the same engine but was wondering if there is something different in the drive train or supension. TIA
Vernon
92 318IC
64 El Camino pro street
87 325 (long gone) best car I ever had 300,000+ miles

[rjp325i]

In 1991 there was a 318i (4 dr), a 318is (2 dr) and a 318ic (cabrio). In 1992 you have a 318ic (cabrio) which along with the 325ic is the last of the E30 model line. The rest of the 1992 line are E36 models. The s models have a sport suspension which means it has slightly stiffer struts/shocks and springs that allow it to sit a little lower by about a half inch. The convertible uses slightly heavier springs due to the increased weight and stronger rear shock mounts than the other models. I do not believe they used the s struts and shocks but an owner of one of these might have a better answer. The shock mounts for all E30s are still inferior to the later E36 and E46 mounts however. The newer ones are a direct replacement if/when you upgrade or have to replace.

[///m42 sport]

I got some e46 rear shock mounts to go with bilsteins and h/r and they still blew! I would just get the one piece aluminum mounts or the ones with urethane replaceable bushings.

[rjp325i]

I know what you mean. I installed the E30ic mounts in April. One blew and the other cracked. They lasted 6 mo and 7K miles. I have E36 (E46 were out of stock) cabrio mounts in there now and am hoping they would do better. They were recommended to me by several people with E30s. Like you say the billet mounts are next level up. When I was talking to Will Turner at our last club mtg I aked him about the mounts. It seems to him a lot depends on the manufacturer. I don't know. If/when these go I'll go with billets. I was also wondering if I would be trading one problem for another. Would I start punching out the metal with the billet mounts since they are stronger yet? I am running H&R OE Sports, Bilstein HD struts/shocks, Eibach sway bars and stress bar, offset control arm bushings on my '89 325i coupe. I suspect that the stresses are more in a cabrio that is why they are "stronger" to begin with. The stock mounts with stock suspension me lasted 14+ years.