oil is mixing with coolant in motor and reservoirs, does not want to start but run great when it does, still has lots of power, smoke under power, top end was rebuilt 3 weeks ago. HELP this is my first audi

 

I am a super noob to here but I have a 2001 a4 1.8t auto/tip (sadly) and I don't know how to start a new thread, I'm guessing I don't have those rights yet�� but I saw this stage 1 ecu on eBay (yes I know...eBay is bad) but I wanted to know if anyone has it or has seen it? Let me know if it's decent or not?

01 Audi A4 1 8T 4B0906018M Stage 1 ECU Tune 55HP Option to Remove Cat | eBay