Preamp or DAC?

Been slowly building my system and have a pretty decent amp, a Benchmark AHB2. Funds are limited, but ready to get either the Benchmark DAC3 or their bit more expensive LA4 preamp. Trying to keep it all in the family. Recommendations regarding which one would be best choice since can only afford one or other? Wish I could get both, but don’t make that kind of money (maybe in a year or two). For context, feeding it with a streaming Bluesound Node 2i and delivered to Selah 4 ohm floor speakers. My audio knowledge is limited, especially compared to most of you all, so any advice you may offer will be much appreciated. Feel the need to see what you "experts" think before purchasing. Thanks!