The only real prob with the OEM TIP is that it is prone to collapse on itself at high revs restricting airflow, some have a reinforcing metal insert in which sorts, later models have stronger/thicker ribbing to prevent the collapse from happening. Mostly the silicone TIP wil solve this as its stronger especially when the engine bay gets warm plus it looks good.
Performance wise it doesn't really do much, some report the engine seems to be more responsive, others report that you can hear the turbo spooling and the DV working more clearly... swings and....
I have an Autobahnn 88 TIP I got from ebay for about £60, its fine, no drama and looks good.
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