Typically Toyota rngine codes are as follows. eg 4AGE: 4 - 4th design revision, A - Engine Series, G - Wide valve performance design head typically from Yamaha, E - EFI eg 3SGE: 3 - 3rd design revision of S Engine, G- Performance Head, E - EFI. eg 4AFE: 4 the revision of A engine, F - Narrow angle valve layout for economy, E - EFI. A T later in the name means turbo, Like in 3SGTE - So thats 3rd revion of S engine, with performance head, turbo, and efi. Dont confuse this with the earlier series of Engines, the T engines, eg 3TC, 3TGTE which is the 3rd T engine desin with a carb or turbo efi respectively. Over time they added more codes for more features. A Z Later on in the name typically refers to a supercharger, eg 4AGZE. It gets weirder the later the motor, with most Toyota engines now featuring two letter model designations, Like UZ, ZZ, AZ, NZ, MZ, VZ, GR, GZ, JZ etc, and these typically are just engines produced after a certain date, but it gets confusing when they reuse letters that used to mean SC in the engine codes. Some new tech that came out got different designations in the name, for example, an gernerator tuned engine that a hybrid uses is Usually designated with an X, For example the camry hybrid 2AZFXE. The direct Injection motors are S designated, for example 2GRFSE. If thats all clear as mud then factor in how enhusiasts like to build and name their own combos, from which weve seen things like the 1.5JZ, for the man who wants more power but wont upgrade turbo, heads and manfolds on his 1JZ build, or the 7age, Which is the 1.8A 4AF engine with the GE head. This is extra confusing with the 4age aftermarket, because an original takao special 7ag is just specific build of 4a 1600 that revs super high, but a later enthusiast will think its 1.8 litres. So yeah long answer to what should have been a simple question. Heres a pic of the Beams 6 speed, the starter is in a good spot at least at first glance its on the inlet side of the engine, so if its in the right spot compared to the block you could do what I have done and just chop away some extra block and give yourself the clearance you need. To be honest, a 6 speed would be a nice addition because it has the power to highway drive an ae86 at 1800rpm but it does 2900 at 100kph. Even with a 3.58 rear end gearset. You could run 3.9 or 4.1 gears and be perfectly happy with it, and make the engine haul the IS body around a bit more spritely when youre not in overdrive. To clarify my comments, the 6 cylinder G engine in the Altezza shares the pattern with the older T engine, which makes your transmission an upgrade for older corolla and celica platform cars, E and A chassis codes, that had a T engine. So thats who could use your box aside from an altezza G engine owner. I'd suggest to offload the G box and swap it for the S pattern 6 speed from the RS200 altezza, and then the 2azfe would at least connect to the box thats in the car, and you can start investigating clearances for inlet, exhaist, steering, crossmembers etc.