TechArt will not release their spring rates so it is an unknown. And Eibach will not release the rates as well. From the comments the rates are most likely the same but a shorter spring to lower the car.

This has been done. Check out BGB Motorsports thread.
https://rennlist.com/forums/991/1060...ep-thread.html

Not at all uncommon for a large manufacturer to make products for smaller companies, to their bespoke specs. As but one example is Vossen wheels. They make their own wheels, and wheels for Champion Motorsports, along with several others. The Champion wheel specs are bespoke to Champion; many consider Champion Wheels superior and worth the added cost; the weights are lower and the designs are different. The differences, in this case, are measurable and visible to us.
Eibach makes springs for numerous small companies and tuners - not just Tecart/Porsche. Quite common in the automoive world and manufacturing in general.
The Techart springs are made to specs that allow for a small, but noticeable improvement in cornering. The other benefit encountered by Porsche owners of Techart springs, is an extended service life over "standard" Eibachs. The Eibachs are quite good, and would be my choice if I did not intend to keep my 997.2 C4S for many years.
Each of us, of course, choose where to spend our hard earned Porsche Dollars and where we will receive the most gain per dollar for our desired results.
Techarts are a great combo with my PASM, DSC controller, front tower strut brace, and forged wheels with Cup 2 tires.

I'd argue that Eibachs will have the most extended life of the shocks due to the most conservative drop. For the money it's hard to justify Techart since once on the car nobody will be able to tell the difference in such a close right height and the jury is out on spring rate, ride, handling with no objective data whatsoever[compared to eibach]. Luckily is only hundreds of dollars difference and not thousands but its still a big %.

Ride height with the two are the same. Strut life and spring life are extended, given driving conditions are comparable.

I have owned and driven on Eibachs, very good. Techart diffrence can be felt. There is no additional "middle-man", as we buy Eibachs from a vendor. In the case of Techart products, we can purchase from Techart - no additional hands to pass through.

Those of us with Techart products (or any smaller dedicated car product manufacturer) prefer those products, and know we pay additional for the small but noticeable improvements. There are also other vendors that offer aftermarket springs for our cars, each with their version of what can be improved upon. Eibach and H&R make springs to a price point, for the masses.
I prefer Champion wheels to Vossen - same parent - different offspring. Those that don't appreciate the improvements, should not spend the additional dollars - spend it elsewhere towards what you feel is important.

Techart have slightly more drop than Eibachs.

There is an additional middle man...

Eibach > retailer > Consumer
Eibach > Techart > retailer > Consumer

Again - I have no data to backup one being superior in any way and I don't think you do either. I'm just suggesting that my perception is that with Techart you are paying much more for a name/brand and that factually the eibach branded springs have a more conservative drop and it is my hypothesis that this will extend the life of the shocks. Even if Techart was slightly better - they are price gouging based on the brand given the % in price delta.

Ride height is the same between the two. I have owned and used both.
There is no an additional middle man ... I purchased from Techart.

Eibach > retailer > Mass Consumer
Eibach > Techart > Consumer

I was considering both the techart and H&R springs but went with an alternative with GMG lowering springs. Worked well and GMG is a local vendor here so I got a bit of a discount buying and having the springs installed by them.

https://cimg7.ibsrv.net/gimg/rennlis...ce6ca23b09.jpg

https://cimg8.ibsrv.net/gimg/rennlis...e84e4cc535.jpg

So far very happy with the results, they're PASM compatible and don't change the ride quality at all in normal or sport mode.

WORLD of difference.

I'm so glad the previous owner of my car decided to lower it with H&R springs. I never would have myself, and it's the #1 factor that makes my car stand out. It just ties up the design and brings out all its best features.

I loved my Techart Springs and GEO, I miss it !


https://cimg4.ibsrv.net/gimg/rennlis...3a4853fe5f.jpg

I'm assuming springs are not a DIY project for a regular guy?

Correct, unless you have a very good knowledge some specialist tools and the ability to string a car for Geo. If you need to ask then the answer is definitely garage only !

I do....But they have like 40k miles on them. Also have TechArt Springs. I replaced everything with damptronics.

but shipping might make things more challenging.