I have the above mentioned car. I would like to replace the rear springs as they are worn out. The car is my daily driver and I was looking at the IPD overload springs and rear Bilstein HDs. I have their sway bars on the car. I do not want it to ride like my F350 though.

I just installed the overload springs with new Boge touring springs, and I can tell you the ride is just fine. Firm but not harsh, and will handle a huge amount of cargo without sagging. I went with the Boge as popular opinion seemed to be that Bilstiens were too much for a wife-driven daily driver. At least, driven daily by a non-racing-enthusiast wife.

Post over on Turbobricks, lots of experience over there.

I have Bilstein HD's, have had them in two cars, now in a 93T which has stiffer springs than stock apparently, certainly thicker than my 90 740.
I would Never in a Million Years, combine these with heavy duty springs. If I make any money in the near term I'm going to take them out actually, or possibly put in the thinner springs.