We had the pleasure of working on Steve's beautiful Nardo Grey MK2 R8 V10 Plus. He came in for a V-Style CT Carbon Kit consisting of front splitter, rear diffuser and this much larger than OEM spoiler. Steve then visited us again shortly after to add the side skirts onto the car aswell. 
Even though the kit only consisted of 3 pieces (excluding the side skirts), it was a very involved process to get all of this to fit perfectly. The bootlid or arguably the engine bay cover had to be removed to allow the removal of the OEM Spoiler cover. The rear bumper had to come off the car to grant clip release. This also allows us access certain bolts and to ensure a flawless fit of the aftermarket diffuser. 
The spoiler was by far the most challenging and meticulous part of the transformation. Without spilling too many trade secrets... shaping of the spoiler was required, rivnuts had to be inserted and gaskets had to be made to ensure no moisture entry underneath the spoiler. After measuring twice and drilling once, the newly inserted riv nuts lined up perfectly to the OEM spoiler mounting holes and we were able to retain factory hardware which is always our goal. This way the entire process is also reversible without trace.
The diffuser on the other hand wasn't anywhere near as complex, just time consuming. We again, retained all factory fixings and managed to tie it into the undertray. We also bolted the diffuser to pre threaded chassis brace holes in two locations which actually makes this construction sturdier than OEM.
The front splitter was as always nylock nut & bolted to the bumper. As these splitters tend to be hollow, we use a hole saw to make an 'access hole' to ensure when bolting the splitter up we aren't tightening the bolt into a hollow chamber which could cause spider cracking of the material. This way, we also avoid the lowest part of the splitter being fixing hardware which could get caught on the floor and cause significant damage. We've seen many aero parts installed previously with bolts or screws being the lowest point.
Here is the finished result:
A few weeks later Steve came back to have some carbon side skirts fitted to match the rest of the kit.
These needed the jacking points cutting out to be future proof. We used rubnuts to fit these with stainless steel hardware to match.