Ultram is an OK substance, and I have a LOT of experiance with it, and the shit will get you high.
As to what someone said about Ultram containing APAP, is does NOT. They did come out with a new drug, Ultracet, which contains tramadol and APAP, I think that is what you were refering to.
Now, Ultram is some OK shit, but I'm trying to give you good advice, so here it is. Hydrocodone is BY FAR a better choice then tramadol in my opinion, and I'm sure anyone with actual opiate experiance will tell you.
Conclusion, get the Hydrocodone, you don't even have to worry about the APAP levels you are consuming if 20mg oxy has you lit and 40 has you puking. I say a dose of 6 5mg hydrocodone pills would have you REAL lit, and that is only 3g of APAP, which is not a very large dose at all, completley safe.