• Buffer a fulljump while holding D+R
• Complete the rest of the level without slowing down*
• Do a D70 top step FFPG

This is an easy setup, though it of course requires finishing the level without slowing down, and it gives first frame 325, barely avoiding 6 fireworks. This is also the current fastest setup aside from mavpoling.

*In the tunnel part where you normally have to fall down into a hole and jump out to avoid an enemy, if you do a 1 frame jump on the last frame before Impos falls off, you'll bop the enemy, allowing Impos to pass through without slowing down.