All the complaints about 240d and 300d dash lights are easily solved with 10 WATT Xenon bulbs from Bulbs.com or 1000bulbs.com - put them in a friend's 240d and the cluster is lit up like a modern one - the factory used a ridiculous 3 watt bulb and the most you can get in a parts store is 4.6 watts in a 168 bulb
Bulbrite 715510 - 10 Watt - T3.25 base

I would be very concerned about the heat generated by a 10 watt halogen bulb. You would likely melt the instrument cluster plastic, etc.

I would stay with the stock bulbs or go LED.

Sincerely,

PE