))) new TS exhaust question (((

[aucorium]

hey guys

i did a cat back exhaust on my TS , 57mm pipe all the way to the back , kept the OE resonator in , but got a megan racing rear exhaust muffler , car pulls alot stronger from the bottom , but seems to be lacking on top a little now , should i have gone smaller ? like 50mm ? as the OEM pipe size is approx 45mm from the factory , i feel from pull away its much stronger , but seems to fade out at high speeds a little , will a smaller exhaust pipe work better ? should i give the ECU time to learn first ? should i go smaller to 52mm mabye ? or 50mm ?