contitech bags on my 86 s15

sd's cups are a life saver you'll spend more in material building your own.. the diamter of the cup is 5", tops are 3" bottoms are 2.5 i think if i remember right, i'll measure a set i have out later on.. as far as the plate on the bottom of the cup, its 6".

the good thing about sd's cups are the new ones are offset so you dont have to hack the hell out of your frame for 2600's like we had to in the past. With SD's new cups, you cut the front out all the way to about 2" from the top of the pocket, then on the sides, i did it all the way to the frame on both sides and in the back you take off the lip, plus you cut the very back part flush.

before u'd have to cut into the frame in the back and replate it.

as for the no sharp corners.. as long as you dont leave saw cuts unwelded, you wont crack anything.. mine has been 'sharp cornered' for 2 years now, and it hops daily and not 1 crack.

here is a pic of the front of mine.

guess you're lucky on not cracking, i saw one not long ago that had only been bagged a few months and was cut almost exactly like that, and it was craked about 2" already

and i can bet you he had left parts of the cut out unwelded.. i.e. you cut too far and its cut a little too long.. cracks run from there.. cracks arent going to form on corners that dont have anything to lead from.

could be, i just saw the pictures of the cracks, I didn't do the work...