Grand Ayatollahs Imam Khomeini, Bahjat, Khamenei and Saafi:  One who has performed jinabat ghusl mustn’t perform wudu in order to offer his prayers, but one must perform wudu after he has performed another obligatory or mustahab ghusl. [1]
 
Ayatollah Fazel:  One who has performed jinabat ghusl mustn’t perform wudu if he wants to offer his prayers.  If one has performed other obligatory ghusl, except medium Istihadah ghusl, [2] then one would be able to offer hisher prayers without wudu, although it is better to perform wudu as well. [3]
 
Grand Ayatollahs Khoei, Tabrizi, Sistani, Noori, Zanjani and Vahid:  One who has performed jinabat ghusl mustn’t perform wudu in order to offer prayers.  If one has performed other mustahab and obligatory ghusl except medium Istihadah ghusl, one would be able to offer hisher prayers without wudu, although one is supposed to perform wudu as well, according to a recommended (mustahab) precaution.
 
Ayatollah Makarem:  One is allowed to offer his prayer by any obligatory and mustahab ghusl such as jinabat or other one, but, according to a recommended precaution, one should perform wudu if he has performed other ghusl but jinabat. [4]
 
In Conclusion:  One has to perform wudu if heshe wants to offer hisher prayers, however he has performed a mustahab ghusl, according to the fatwa of grand Ayatollahs Imam Khomeini, Bahjat, Khamenei, Safi Golpayegani and Fazel Lankarani.
However, according to the fatwa of grand Ayatollahs Khoei, Tabrizi, Sistani, Makarem, Noori, Zanjani and Vahid, one is allowed to offer his prayer by mustahab ghusl, however, according to a recommended precaution, one is supposed to perform wudu if he has performed mustahab ghusl.
May Allah, the Almighty grant you success and long life.

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