Exhaust Headers for Toyota MR2 (1990-1995) 2.2L EngineHigh Flow 4 1 Stainless Steel Exhaust Headers for 1990 1995 Toyota MR2 (SW21 5S FE) What it Does: Replaces the restrictive factory cast iron manifold with a mandrel bent 4 1 stainless steel system to optimize exhaust scavenging and increase volumetric efficiency on the naturally aspirated 2. 2L engine. The Stock MR2 Exhaust Constraint The OEM manifold found on the SW21 Toyota MR2 is a heavy cast iron unit designed primarily for manufacturing economy