>>1288100Go for white tape, it matches the saddle, and if you get fizik microlight tape it's easy to keep clean with a 'magic eraser'. I would not try include any kind of yellow accent unless the accents were very subtle indeed (thinking of something like pic related).
>>1288205It doesn't really matter - the main difference between group tiers is weight savings. In the past Shimano put fancier hoods on their Dura Ace shifters, and had crappy low-end shifters with ergonomically inferior thumb buttons, and there's still the difference between Ultra/Powershift at different levels of Campy, but shift quality doesn't fundamentally change between group tiers.
For derailers this cannot be overstated: there's essentially no real difference between models in the same family other than that the higher end ones save you a few grams. They work exactly the same.
If I had to pick one to upgrade first, it would be the shifters because they weigh more than derailers, so savings there are more significant.