The HKS Max IV gets away with a short body and no accumulator because it has a larger in diameter body for more gas volume. You can see that since the mounting clevis is adjustable, the ride height can be lowered wile still maintaining good bump and droop travel. The HKS coilovers are preset for the optimal ride height for most situations so avoid the temptation to make them lower by screwing the clevis in more, you will end up bottoming in the wheel wells or worse.
The HKS Max 4 coilovers bolt right in very easily in the rear.
On the fuel filler side, this flex shaft bolts to the shock adjuster rod. The flex shaft bends around the fuel filler pipe and sticks into the trunk where you can reach it easily. This is a really good small detail that others forget!
Here is how the adjuster is now accessible. Can you imagine adjusting the shock without it?
Removing the front shocks is a little more involved. First you unbolt the top mounts from under the hood.