You could simply buy spray and fit but IMO if you don’t put in a little extra work in the form of cutting down it will look odd when fitted as to get boot lid clearance the supports need to be sat over the rear light clusters like this –
This guide will show you how to modify the spoiler to better fit the car.
Main Costs
£173 - Spoiler from- http://www.elisepart...4-rear-spoiler/
£12.98 - 1 x can of Upol Clear #1 UV Resistant Clear Coat Lacquer Spray
£11.99 - 1 x 400ml Custom Colour Aerosol
£6.49 - 1 x Halfords Filler Primer Spray
£8.50 - P38 or equivalent Body Filler
£8.50 - P40 or equivalent Glass fibre paste
Around £70 for enough 3M 1080 Carbon Wrap to cover the blade or around the same to get it sprayed black somewhere. (Would not really reccommend attempting with rattle cans due to large surface area)
Other Things Required
Masking tape
Blu tac, pens, measuring tape, Allen keys
Thread lock
Coupler bolts (available from Homebase for about £1.50 a pack) or another deep M6(?) nut of some sort
Nylock nuts to replace the originals (optional)
Various grades of sand paper (easier with an electric handheld detail sander)
Dremel type cutter or coping saw
Sheet metal to strenghten clam and jigsaw to cut it to shape
Drill and HSS bits
10/11 socket or spanner
For your spray paint I can highly recommend paints4u.co.uk fast service and a good colour match. You can find your paint code on the drivers sill or via this link - http://www.lotuscars.../paintcodes.php Give them a call stating your colour code and order the cans listed above.
Firstly assemble the spoiler and place it on the clam as central as you can and as far back as it needs to be for the boot to open. Looking at the crease line in the clam in front of the light cluster try and continue the line diagonally across the bottom of the support and mark two points either side so that when cut the support will follow this angle.
I found that the rear most moulded in nut seen on the base was a good point to aim for. I cut diagonally across up to this only just keeping it intact. It will not be used anyway now as it’s too near the edge so cut through it if needs be.
With your reference points marked disassemble the spoiler and draw on the rest of your cut lines. This is mostly down to personal preference, I choose to go part way up into the area in which the edge gets narrower thus keeping a defined and jagged edge in the same style as the rest of the support.
Anywhere along those lines shown should do. Now using your Dremel or coping saw cut from the base up. Use a slow speed or the plastic will melt creating a rougher cut that is harder to smooth down. It is better to cut slightly in front of your lines first and then work up to them bit by bit as it’s easier to take bits off than to have to add more back on.
Once you are happy with your cuts the next stage is to put in a replacement encapsulated nut for bolting into. Drill a tight fitting hole in the middle of the underside around the same distance in as the remaining front nut. Hammer your coupler bolt in until it is flush with the bottom and then mix up some glass paste to spread around the inside to support it and stop it spinning.
You should have good enough access to the hollow innards from your cut down edge to get a small spatula tool inside.
You are now ready to rebuild and shape your new side. Start bridging across with some P40 and create a sort of dipped trough as seen above. Key the edges it will be sat on by roughening them up and make sure the glass paste is pressed into the surface to ensure a good bond. Once this has cured mix up some body filler and apply liberally until you have a mound that is protruding out quite some way. Wait until the fillers are cool to the touch and set hard before going onto the next stage.
When sanded the body filler will just powder away leaving a very smooth finish. Just keep sanding away until you have shaped an edge you are happy with. Now spray all over with your filler primer and smooth back again with a finer grit paper. Any minor surface imperfections at this stage should be quite clear to spot so get them all corrected and when dry and clean spray your base coat of colour matched paint.
A good finish will be dependant on spraying technique and the quality of your prep. Shake well before use and keep the can moving accross and beyond the surface at all times. Several light coats are better than one heavy one that will be much more likely to run. The laquer will need to be applied quite heavilly to be smooth to the touch and give a deep shine. Just using lighter coats of this seems to just grit up on the surface and feel rough. It may be best to lay flat and do a side at a time so gravity is helping you. This stuff is so clear you are very unlikely to spot overlaps or thick thin areas. Once complete polish and wax them ready for fitting.
Carbon wrapped blade -
The 3M 1080 series carbon wrap is very workable and quite forgiving in use. However it still took me around an hour and a half to do the blade and despite it's simple shape it is not the easiest thing to wrap in one piece. My results where acceptable but there are a few imperfections. A 100 by 150cm length was enough to cover it with a few decent sized off cuts. This cost around £70 and I would imagine to have it painted would cost roughly the same.
With all your parts now prepared, loosely assemble them and place on the car. Mask up the area it sits on and trace around the footprint of the supports where you are sure you want them to go. Remember to check for boot lid clearance again. You will find that how flat the support will sit against the clam will depend on how tight you have the allen head bolts done up. Leave them loose at this stage so that the blade rattles a little, any slack will be taken up when you tighten them properly once the supports are secure. The method I used to determine where the holes needed to be drilled was to put a bit of blu tac into the nut hole and then but a blob of ink onto the middle of it. When placed back onto your outline the ink will transfer accross to the masking tape showing you exactly where to drill so you can be sure it will align correctly. Check everything and then check everything again then pick up your drill! When drilling use decent quality drill bits I used HSS bits which is overkill for the soft clamshell but they will not tear at the surface and will achieve a nice clean hole. Drill very slowly in short bursts and try not to put much pressure on the tip as you are more likely to splinter the underside of the hole when you punch through.
With your 4 holes drilled very carefully remove the masking tape. Do not become complacent when doing this it is very easy to tear it off a bit quick and take a bit of lacquer with it! Blue detailing tape is better than household white stuff if you have any.
looks much better, slightly cut down as you've done. 
