The TTR and XT 225 use the same stainless steel header which will bolt up directly to a FMF Powercore on your 2011 TW(If you buy the FMF model made for a TW200) . There have been reports of the FMF muffler not aligning properly on some of the older TW's. I suspect they bought the TTR 225 FMF model. FMF reps have told me that the FMF is direct replacement for all model year TWs. The OEM exhuast is the same for all years, so why would the FMF not fit all years. The 2007 XT225 is the last year with a stainless header. The OEM part number is the same for the TTR and XT225.
The DG series oval and round series mufflers are direct replacements for the OEM and will work (bolt on)with the XT225 header. I have the oval and stainless header. They are less expensive than the FMF and have the mounts for the muffler heat shield.
http://cgi.ebay.com/ebaymotors/DG-O-Series-Slip-Exhaust-Yamaha-TW200-dg-03-4205-/200593662080
http://www.denniskirk.com/jsp/product_catalog/Product.jsp?productId=p435448#fitment
Dusty
An updtae to this post! I posted some inaccurate info-although it was based on the best available info at the time!. The stock pipe bolts up fine to the DG Oval exhaust made for the TW. It does not quite bolt up to the TTR225 header. I missed something in my loose fit-up. The TTR225 pipe has an outward notch that stops it from going in far enough into the muffler to bolt up. I thought about grinding the notch down or cutting the pipe shorter. The pipe is longer than the TW OEM so I cut it just beyond the notch, ground the edges, worked it a few times and it bolted up.
So, to recap:
1. OEM header and TW specific FMF muffler=bolt on. (2003 and beyond)
2. OEM header and TW specific DG muffler=bolt on. (2003 and beyond)
3. TTR 225 stainless header and FMF muffler=bolt on (2003 and beyond)
4. TTR 225 stainless header and DG muffler= cut the header (or add spacers to front and rear) and then bolt on. (2003 and beyond)
5. 2002 and prior bikes: The 2002 and prior bikes have a slightly shorter mounting tab on the frame and a slightly shorter distance between the two mounting points on the muffler. A short spacer is needed to link a 2002 or older OEM header to a FMF or DG muffler made for the TW "all years".
OEM muffler part numbers:
2JX-14711-00-00 1987-2002
2JX-14711-10-00 2003-2012
http://tw200forum.com/index.php?/topic/2500-oem-muffler-exhaust-interchangeability-between-years/
http://tw200forum.com/index.php?/topic/2669-after-market-exhaust-dg-fmf/