The length and the angles of the 4 links are a very much indeed important. It is also more important to have them longer than shorter for the most part because you will want the room for tire clearance where the front links will be and they need to be out of the circumferance of the tire where he has them if he plans on running the widest wheel and tire he can. Every 1/4" is a mile when it comes to clearance.
You can go into the back seat area and gain a ton more strength and still be able to put the back seat in and have it cover them.
Once you do it you will never do it again because it is harder than starting from scratch, which is why I cut my floor and trunk out and did just that. it is a lot cleaner and just as easy to replace all the area with new and packaged to fit what you want.
Google the word " Cormaro" and you will find quite a bit more about my car or just ask.
Have fun!!!!