I am fixing a 87 TSi up and the turbo is bad. I want to get 300-400hp out of it and I was told 300hp was pushing it with the stock turbo . I was wondering could I use a 88-89 turbo (direct bolt in) or would I need to modify it also I was told I could have it port & polished or something of that sort to make it flow more air what would you guys use??? also what after markets could I use direct bolt in???