I've been running nearly all of my interior lights with LED bulbs for over a year now but it is important to get the correct ones. For the speedo and tacho you need a 180deg bulb as in the link. This is important because the light has to be spread laterally as well as forward to light up the entire clock. If you use the forward firing type, as indeed a good few sellers are recommending as the correct type, you will get a bright light at 4 and 8 o clock and nothing else. Do not be tempted to buy the longer model, it won't fit. If you have canbus issues, the T10 is widely available in the style of the second link.
10 T10 W5W 168 194 Bright White 5 SMD LED Side Wedge Light Bulb Lamp | eBay
2 CANBUS T10 W5W 194 5 SMD LED Car Side Light Bulb Lamp | eBay
For the smaller warning lights in the instrument binnacle, a forward firing T5 bulb is the one to use. If you can get the type with the diode flat mounted on top, as below, they work best. Sorting out the polarity is a bit of a pain but it is
just possible, if a little tight, to connect one of the plugs with the binnacle out. I have replaced all my switches and the seat heaters with blue LEDs but the speedo and tacho were done with bright white (
pale green), because I like that. Many of the T5 bulbs are available as a warm white if you prefer but I replaced my high beam with a blue LED because I found I wasn't aware it was on, too often. Although it doesn't distract me now, I am aware from the resulting halo that I have the mains on.
2X T5 286 5050 SMD LED Car Wedge Speedo Dashboard Side Light Bulb White DC 12V | eBay
Despite repeated attempts, because of the construction of the cluster of switches down by the drivers knee, I was unable to convert these and so they remain green. I also did a nifty mod to the window switches where the "auto" is lit in blue but I have blue LED dots, around 3mm diameter, in the middle of the other three buttons.
The cabin light was converted to a 6x3 LED board and I have an array in the rear cargo area that can be switched in or out but when on, you can do any kind of work you like.
The auto timed dimming works on the cabin light and the dashboard dimmer works fine. As Backpacker said, the blue is funky but makes it hard to see the needles so from a safety point of view,
maybe not the best choice. I have T10 1.5 watt LEDS in the front parking lights, which pass the law ok, and while I experimented with rear stop/brake LEDs, I found them to be lacking in definition between tail and stop brightness and so abandoned them. Having travelled behind the newer high end German and Japanese cars with the LED arrays in the rear lights, I find them blinding to the point of excluding your vision beyond the car in front so I expect I will not be going this route at all. LED turn indicators are cool in the day time but personally, I think they are dangerous to other road users at night and especially in dark and rainy weather as they can "starburst" in the other drivers windows, so I left the incandescents in place.
I have been mucking around with LEDs for years and spent a while trying out lots of different types before settling where I am and IMO, the Ebay ones coming out of China/Hong Kong are absolutely fine and way less expensive than domestically sourced parts. Often the local item costing ten times as much probably came from the same factory. Your choice but if you are experimenting, this might be the more cost effective option. My only 'solid' advice is the particular type for each application.