I personally would go the fueling route. While it is true the TMIC end tanks are known to crap out at 19 psi or greater, there is a bulletproof mod you can do to the endtanks to reinforce them. I will find the link for you. In the end, you will benefit more from better fueling than you will from an upgraded IC. Get that the next time around.
EDIT: Thank God for the LegacyGT forum. Mad props to them since NASIOC deleted or hid the forums regarding the bulletproof endtank mod. Here is a link to get you in the right direction. Despite it's smaller size, the OEM WRX intercooler is quite efficient when the tanks are reinforced. Hope this helps.