"You know how hot it gets in So.Cal."
Ha! Ever heard the saying "If I owned a house in Texas and a house in hell, I'd live in hell and rent out Texas" ?
The '99 fan really does cool better ... I can testify to that. I recently put one on my '95 as it was having definite cooling problems at the track in the August heat (so was I for that matter). Can't comment on the diameter difference (if any) between the '95 & '99 fan, but I do know that the '99 has curved vanes at the tips of the blades whereas the '95 does not. Furthermore the '99 and it's shroud is centered on the radiator whereas the '95 is not. More importantly I noticed a 10-15 degree F decrease in peak temps using a stock 190 F thermostat. The fan module was installed by David Weaver of Maxwell Dodge here in Austin. He surfs this board periodically so maybe he can tell you more if you need info.
I recently sold the '95 and bought a '99 coupe and it runs noticeably cooler than the stock '95 did, so there's two data points for you. The fan module runs about $190 with about two hrs labor for install ... total ~ $300. Well worth it in my opinion.
