People can correct me if i'm wrong, But i had two skyline's, One is a normal (RB25DE) and the other is a (RB25DE) TYPE M But now it turbo, and the difference between them is:
One is A/C
Two is Rear Stabilizer
Third is Four Wheel Steer
Fourth is LSD Diff
Firth is Rear Wiper
And the interior is no different in both, can tell you about the exterior cause one has a body kit....
But that the difference that i have found... And i always throught that non-turbo skylines had the type m, And turbo model skylines had the spec m