To improve overall performance there is no better mod than weight reduction. With a lower weight the car will accelerate faster, corner faster, brake shorter, and the transitions between all these, or from corner-to-corner, will be improved. It's just a win win win.

Let's use this thread to collect weight reduction ideas. While different people all have different goals and different tolerances for radical mods, I think a 100 lb weight reduction should not be too hard with reasonable mods, and maybe 200 lbs is possible with a determined effort.

I'll start with a few well-documented items, and then let's all collaborate to identify the best ideas for reducing the Cayman's weight.

This mod is well-documented with an article in the performance mods category ETX14 Lightweight Battery for the Track. It is inexpensive, easy to do, and reversible. The only downside appears to be that the smaller battery will not maintain its charge if the car is not driven for a long time, especially in the winter. A simple trickle charger solves this problem.

The "toolkit" in the front boot has little value in the absense of a spare tire. One can either remove it and rely on Porsche Roadside Assistance, or just take it out for track and AX days. In any case, an easy 9 lbs.

Switching to lightweight wheels can provide a significant weight reduction. This particular weight reduction provides a double bonus - it also reduces unsprung weight (improving handling over bumps) and reduces rotational inertia that must be overcome (in addition to the weight) to accelerate or deaccelerate the car. By my estimate the rotational inertia effect doubles the benefit of lightweight wheels, in terms of the increased acceleration. The amount of weight reduction will depend on what wheels one currently has installed, and what lightweight wheels are selected, but 20 lbs is a reasonable expectation. In my case, switching from OEM 18" CS wheels to Champion RS98 1 piece forged wheels should provide about 19 lbs of weight reduction.

Edit: the RS98's have come in well over their weight target, and the actual weight reduction was only 14 lb.

The Sharkwerks lightweight flywheel weighs 14 lbs less than the OEM dual mass flywheel SharkWerks Light Weight Flywheel Kit. This mod has the bonus that it significantly reduces rotational inertia, especially in the lower gears. There have been a number of estimates of this benefit, but no definitive calculations or measurements. The estimates are typically in the order of a 5-7% reduction in total inertia (weight plus rotational inertia) in 1st gear, dropping to 2-3% in 2nd gear, and diminishing further in higher gears.

There are some downsides to this mod in terms of increased noise, and possibly increased gearbox wear SharkWerks Light Weight Flywheel Kit. But everyone who has a lightweight flywheel seems to love it.

The various aftermarket catback exhausts have different weights, but they are all lighter than the OEM exhaust. To establish a rough range, the Borla catback weighs about 8 lb less than stock Borla Catback Exhaust (PN:12653), and the Supersprint weighs about 16 lbs less than stock SUPERSPRINT Headers/Cats/Muffler install & test. I've cited a wider range in the title of this post since I have not done a comprehensive search - perhaps others can help with this data.

This mod has the bonus of increasing engine power. Power increases ranging from about 5 HP to about 20 HP have been measured by independent dyno tests posted here.

There are downsides to changing the catback. The car will be less neighbor-friendly (louder), and it will no longer comply with EPA and some state regulations, since the aftermarket catback eliminates 2 catalysts.

Switching to lightweight tires has the same double bonus as switching to lightweight wheels - you also benefit from a reduction in unsprung weight and a reduction in rotational inertia. The rotational inertia benefit is even greater than it is for wheels, since so much of the tire's weight is concentrated in the tread. So the weight reduction might be worth 3 times its nominal value in terms of the benefit to acceleration.

The amount of weight reduction depends a lot on what tires one currently has and what tires are selected. Some tires are quite a bit heavier than others. For example, the OEM Bridgestone RE050A tires are heavier than the Continental SportContact 2 OEM tires. The Hoosier A6 and R6 tires are very light.

Implement all of the above changes, and you can save 100 lbs! That wasn't too bad... The next 100 lbs will be harder!

Can someone who has installed lightweight racing seats post the weight of those seats, and the OEM seats as well? I've seen posts that cite a 50 lb weight reduction for this mod...

FF - good thread!

Basing on previous posts and my own lugging out of stock seats (didn't weigh them but they are HEAVY!), changing stock seats to GT3's will net about 50#. Exactly how much would be determined of course by which model of seat you have stock and which ones you are replacing with, of course - so I believe the 50# is a good number to quote in this thread.

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GT Silver CS
1980 Honda CBX
2004 Suzuki SV1000
2006 Subaru Legacy
2002 Honda Insight

6 litres at ~ 1 kg/l, or about 13#

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GT Silver CS
1980 Honda CBX
2004 Suzuki SV1000
2006 Subaru Legacy
2002 Honda Insight