The best thing to do would be to cut the entire floor out,loosing the trunk floor as well.A square tube frame could be constructed,providing you have or can build a frame table. Your beretta body is too narrow to accept a full width vette front or rear cradle,so you'll need to build a jig to set up the front end, using the vette uprights,upper-n-lower control arms, taking into account the need to build in all the propper geometry to make the car handle properly. The same goes for the rearend.You'll have to jig up the center section,the suspension pickup points,etc..Not to mention you'll have to get custom legnth half shafts made. To get the motor to fit under the hood line,you'l need to radicaly set the motor back under the cowl,and prey it'll fit without laying the oil pan on the ground. Of coarse you could always dry sump the motor to pick up a few extra inches of room.Once you've figured out frame design,ride height,wheel and tire combo,brake package,radiator placement ,inner cooler placement,you've plumbed the I/C,brake,and fuel lines,you've figured out how to route exhaust under something that(had better) sits too low,you can now figure out how to attatch the body to the frame.Tying into the rockers is a good start. Then you can build new floor pans,including all the braces for the seats,the body,the tranny tunnel,fire wall,and trunk pan. Because the motor is tucked under the cowl,you'll have to build a custom dash.The interior plastic should work after you modify all of it.You might get lucky and be able to re-use the the body wiring harness after you boil it down to just the things you need. The engine harness should be taken care of with a fast system.Now you can blow it all apart and paint everything, then put it all back together again.I would also suggest upgrading the body to the GTZ stuff.That stuff will look alot cooler than the standard issue Beretta. There's alot of ways to skin this cat.If you hack a bunch of sh!t together,you'll end up with a hacked together hunk of sh!t.This is a massive undertaking,requiring massive amounts of time,work,skill,and especially MONEY! good luck, Chris