When I got my 164e the leather was hard and cracked and even split in a couple of places. I didn't want to spend big bucks on a retrim so I invested $175 in a Leatherique restoration kit. This includes a conditioning oil,cleaner, dye, and crack filler.Enough to do all the seats. The kit recommends that you scrub the leather with paint thinners first and then apply the products in stages over about 4 days. It's actually the old surface coating that goes hard. As soon as you remove it, the leather is soft again. I took the seat covers off the seats and repaired the splits by gluing patches on the inside and filling the cracks on the outside with the crack filler. The filler is flexible and can be sanded down to the surface of the leather before you dye it. It was a lot of work but the result is unbelieveable.The leather is soft and supple and color is back to original. If your leather is not too torn up, this is the way to go. Much better than two grand for a retrim.

If you don't want to retrofit 240 seats to keep it more original then have them recovered by a good auto upholsterer. Or did the 75 164 basically have the 240 seats? I know 73's and 74's were different.

I just had the front seat bottoms done locally on my 244 and it cost me $150 albeit in vinyl. But it looks good. Leather would have been $300. OK I'm cheap. That included new IPD seat grid install that I provided. I delivered the seats and picked them up two days later.

Keep looking for a better deal than $1,700 !

Consider replacing the front seats with leather ones from a 240. I did this on my 75 164. It was a straight bolt in. You should be able to get the drivers seat with a heater that will plug into the connection on the 164. The 240 seats are alot more comfortable that those that came in the 164. At least that's my take on this issue.