Weight reduction
Elise Weight Reduction
Lots of weight to be had from mag wheels, 5.5kg and 7kg - 8>10kg lighter than many Elise wheel sets
Carbon clams are hideous money compared to the weight saved, and dont save much at all unless they are auto claved or vacuum formed. Benetec CF Front Clam 4,95kg Vs std at 15kg but 78k:(
A solid manifold might save you a bit over the standard one if you haven't changed that yet (the Piper solid 4-2-1 is about 7kg) and the adjustable engine steady bar required with it is abouit 1kg lighter than the standard rubber one.
Be very wary of poly side screens. They are very flexible and with the roof fitted flare out dramatically at speeds above 60MPH.
Early rear arch liners are 2.8kg. Later liners are lighter.
Removing the GRP where the reversing light and fog lights are, along with the grilles and the reversing light saves about 1kg.
Don't forget to remove your front mudflaps that are 0.5kg a pair (extra drag as well!) and the leather sill covers that are 1kg.
Alarm siren is 400g, horn a bit less.
passanger subframe is ~2kg and the adjustable driver's one is ~3kg. The seat on its own is around ~8kg
The footwell divider is 8o0g and if you can sort an alternative footrest then theres a saving there, and the gearstick and handbrake covers are ~600g. Pass footrest can go too 400g .
Standar steering wheel is 1.8kg and a raceparts quick release one (inc the relese mech is 750g (but you need to weld a spline onto the end of the column).
The ali boot lit is about 2kg lighter than the GRP one.
The rubber seals around all four wheel arch liners (assuming you haven't ditched the arch liners) are about 200g each, and most of the boot lid seal can be removed with just token parts left in to prevent rattle giving about 1kg of saving.
Exhaust Exige/111R Catback: 13kg. Stage 1 11.8Kg(saves 1.2KG), Stage 2 8,2Kg(saves 4.8KG), , Quicksilver Titanium 5,2KG(saves 7,8KG)
S1 Weight Reduction
-12,5kg Titanium Exhaust system(std 16kg Vs 3.5Kg)
-12,2Kg Carbon fibre track seats (2,4kg vs 8.5 kg) x2
-11,2kg MMC discs insteard of Iron disks (2,7Kg vs 5,5Kg each)
-8.65kg Race battery (2.7 vs 11.35)
-7,25Kg Lexan front window (5kg vs 12,25kg)
-6,8Kg Speedline Magnesium instead of std AWI 5 spoke (25kg vs 31,8kg)
-6.55K Alloy Fuel Tank
-4.4kg Carbon fibre fixed seat frames(2kg and 3kg vs 0,3KG)
-4.4kg Remove the door renforcement on 2 doors
-4kg Remove Radio And speakers (Radio ~1,4Kg speakers ~1,6Kg)
-3,695Kg Softtop and mountings (Top 1,807kg, Siderails 1,888kg)
-3,3Kg Lightweight Flywheel
-2.55Kg Lightweight alternator (3.35 kg vs 5.9kg)
-2,5Kg Cat Replacement Pipe (1.8Kg Vs 4,3Kg)
-2,2Kg Billet Aluminium Crankshaft pulley
-2,136kg Back window
-2Kg Alu top engine mount
-1.994Kg Rollbarcover
-1,697kg Heatsheald bagage compartment
-1.388kg Dressed bagage compartment
-1Kg Carbon fibre steering wheel (1.7kg vs 0.7kg)
-0,872kg Alu Ball joint mounts (1,308kg vs 0,436kg)
-0,8Kg Footwell divider
-0,6kg Handbrake and gearstick cover
-0.55kg Passenger footrest
-0,5kg Front Mudflaps
-0.23kg Inner Rear view mirror
-1/2 of std Lightweight Starter Motor
-2/3 of std Polycarbonate/perspect rearscreen/sidescreens/frontscreen
-?kg Elispart solid 4-2-1 mainfold 6kg std?kg
Other Sorces of Information
http://www.340r.net/technical/weight/weight.htm
http://forums.seloc.org/viewthread.php?tid=91178