Overview Reviews Product Description S-FLO 4” Coupler: The S-FLO 4” Coupler transitions from 4.5” to 4” to accommodate aftermarket turbo inlet pipes that are 4” in diameter. Product Videos Custom Field Product Reviews Write a Review Write a Review × AWE Tuning AWE 4.5" S-FLO 4" Turbo Inlet Coupler for Audi RS 3 / TT RS Rating * Select Rating 1 star (worst) 2 stars 3 stars (average) 4 stars 5 stars (best) Name Review Subject * Comments *