That's awesome.
If the uC has 5V tolerant IO pins, you may be able to get away without using the level shifters. 3.3V is well above the "high" threshold for 5V TTL so most of the time a 3.3V LVTTL line will drive a 5V TTL input without any issues.
If the uC has 5V tolerant IO pins, you may be able to get away without using the level shifters. 3.3V is well above the "high" threshold for 5V TTL so most of the time a 3.3V LVTTL line will drive a 5V TTL input without any issues.