i was running 172Bhp with standard clutch and was slipping big time when giving it some.Took it out and was hardly worn.Uprated after to cope.Standard gearbox will last as long as you as you want,giving you treat it gently and not always giving it some from stand still.Got mate running nearly 240Bhp on standard box on sr1.Hes had no problems.all comes down to the way you treat the car.If you drive like you stole it then it wont last long at all.Hope that helps.