The 23mm Il-2 seems to be missing 2x100kg bombs. As things are now its ordnance capacity is identical to the 37mm Il-2, with a maximum of 4x100kg bombs. From what I understand, the 37mm armament reduced the bomb carrying capacity from 600kg to 400kg (lost a couple of wing hardpoints).
It might be a good idea to split these aircraft in two. Different loadouts, different ENY, etc.
http://www.aircraft-list.com/db/Ilyushin_Il-2/46/Wikipedia also shows the Il-2M3 with 600kg of bombs. Their references include:
* Bergström, Christer. Barbarossa - The Air Battle: July-December 1941. London: Chevron/Ian Allen, 2007. ISBN 978-1-85780-270-2.
* Donald, Donald and Jon Lake, eds. Encyclopedia of World Military Aircraft. London: AIRtime Publishing, 1996. ISBN 1-880588-24-2.
* Glantz, David M. and Harold S. Orenstein. The Battle for Kursk 1943: The Soviet General Staff Study. London: Frank Cass, 1999. ISBN 0-71464-493-5.
* Gordon, Yefim and Sergey Kommissarov. Ilyushin IL-2 and IL-10 Shturmovik. Wiltshire: Crowood Press, 2004. ISBN 1-86126-625-1.
* Green, William and Gordon Swanborough. "The Annals of Ilyusha: Ilyushin's Proliferous Shturmovik" Air Enthusiast, Issue Twelve, April-July 1980. Bromley, Kent, UK: Pilot Press., 1980. pp. 1—10, 71—77. ISSN 0143-5450.
* Gunston, Bill. The Osprey Encyclopedia of Russian Aircraft 1875-1995. London: Osprey, 1995. ISBN 1 85532 405 9.
* Hardesty, Von. Red Phoenix: The Rise of Soviet Air Power, 1941-1945. Washington, DC: Smithsonian Books, 1982. ISBN 1-56098-071-0.
* Liss, Witold. Ilyushin Il-2 (Aircraft in Profile number 88). Leatherhead, Surrey, UK: Profile Publications Ltd., 1968. No ISBN. Reprinted in 1971 and 1982.
* Michulec, Robert. Ił-2 Ił-10. Monografie Lotnicze #22 (in Polish). Gdańsk: AJ-Press, 1999. ISBN 83-86208-33-3.
* Ovčáčík, Michal and Karel Susa. Ilyushin Il-2 Shturmovik: Il-2 Type 3, Il-2 Type 3M,Il-2KR, UIl-2. Prague, Czech Republic: 4+ Publications, 2006. ISBN 80-87045-00-9.
* Шавров, В.Б. История конструкций самолетов в СССР 1938-1950 гг. (3 изд.). (in Russisn) Moscow: Машиностроение, 1994. ISBN 5-217-00477-0. (Shavrov, V.B. Istoriia konstruktskii samoletov v SSSR, 1938-1950 gg. (3rd ed.). translation: History of Aircraft design in USSR: 1938-1950. Moscow: Mashinostroenie Publishing House, 1994. ISBN 5-217-00477-0.)
* Shores, Christopher. Ground Attack Aircraft of World War II. London: Macdonald and Jane's, 1977. ISBN 0-35608-338-1.
* Stapfer, Hans-Heiri. Il-2 Stormovik in Action (Aircraft number 155). Carrollton, TX: Squadron/Signal Publications, Inc., 1995. ISBN 0-89747-341-8.