That's a nice combo, the OS speed and the 2090. I just placed a bid on eBay on the same combo, I hope I'll get it. If I do, I'll let you know how it is.
supposedly the 2090 makes your engine come alive. From what I hear if you don't want to spend the $$$ on a OS pipe then a werks 2058 is a good option. I ran the 2060/ Speed spec II on a buggy and its plenty of power.