Yes, it is possible to interface the 433 MHz Long Range Radio TinyShield with the EFM8UB1-SLSTK2000A via the SPI interface, as long as the voltage levels are compatible and the SPI configuration matches on both ends (clock polarity, phase, etc.). You'll need to configure the EFM8UB1 as an SPI master and ensure proper wiring (MISO, MOSI, SCK, and CS lines). For development, the preferred IDE would be Silicon Labs' Simplicity Studio, which supports the EFM8 series and allows you to write Embedded C code with full access to device configuration tools, code examples, and debugger support. Make sure to check the TinyShield's documentation for any specific commands or initialization sequences required for communication.