Step up your turbo (based on your sig.) LONG before you buy roller rockers. You won't net much power with only a ratio change. 5-10 hp at best. Plenty of guys have run high tens with completely stock engines. (mechanically) If you step up to ported heads and cam, THEN purchase roller rocker and valve covers (needed to clear the roller rockers) Ported heads would also be a better bang for the buck. Roller rockers will REQUIRE trimming the rocker pedistals on the cylinder head, too. Be sure to let your head porter know that you are/might go with roller rockers, and they can quickly trim the pedistals. Roller rockers will set you back over $600 for less than 10 hp. That $600 will buy you 50-60hp in a used turbo.