First, ANY new soft suspension parts will be better than the 50+ year old stuff originally installed at this point.
This means if you can only find "OEM rubber" it is good to go as long as it fits properly.
I have installed many different bushings over the years.
The stiffer poly bushings will provide a stiffer result than the OEM rubber.
There are various durometer bushings available, but you have to do a LOT of homework to get the right parts.
An example may work like this. Lower control arm bushings for your 1965 Mercury full size....best versions are the same as what Chevy used on thier 1987 IROC Camero lower control arm bushings.
Front sway bar bushing for the same car are best served by using the rear bushing as supplied for a 3/4 ton 1976 Camper Special with the 8100 GVWR rating.
Lots and lots and lots of searching to find the "right" parts in some instances.
Otherwise buy a kit and install the whole thing...or go piece by piece from the suto parts store if you can get it.
The bright colored poly bushings usually work okay, but they are often universal in scope and require fitting in many instances.
Plenty of bushings do NOT come with the inner or outer sleeve...and this sucks because if the car is old it usually has some issues with the sleeves.
The poly graphite bushings work well, and provide some self lubrication, but they can squeak and creak just like other poly bushings.
Mixing poly and rubber bushings usually results in deformed and quickly worn rubber bushings.
Adding grease to the poly bushings when installing works great. I make a nice grease from silicone grease and graphite and it works great, but just like ANY greased item the grease eventually wears away, dries up, or stopes working in some manner.
This means if you can get greasable bushings it will serve you better over the long haul, but greasing is not required.
Depending on the ride, look, and feel of the finished suspension work you desire will have a big factor in which bushings to choose.
If you put in a certain bushing and find you really hate those bushings....replace them with something else. Just because you put in new bushings does not mean you HAVE to keep them until they wear out too.
Last, the state of aftermarket parts is horrible these days. The once awesome MOOG and TRW suspension parts are no longer awesome...and some of them are almost pure crap.
In this regard I have found specialized makers seem to have better products.
Places like Energy Suspension have provided good results for me...other than the bright colors they sometimes only offer certain parts in.
Having a whole pile of bright red bushing in an othersie stock 60's car can look a bit off if you are picky.
