strong enough?

I am making a fiberglass sub enclosure for my 95 integra. It will house a Coustic CF124 (12" 400 Watts RMS) I have put 4 layers of glass down so far and my mdf mounting ring is securely fastened to the back piece with 3 1" dowels that I plan on leaving there afterwards. My question is do you think this will be enough glass and supports to keep the enclosure from flexing? I've never built a box completly out of glass before usually had glass backs and MDF fronts. Let me know what you think. Also, the back half of the box will be against the interior pannels of the car.If quiters never win, and winners never quit, who the heck came up with the idea that you should quit while your ahead?

I'm using a fairly thick chop strand mat and polyester resin. The box is 4 layers thick all over and 5 or 6 in large flat areas (reasoning fg is stronger in curves so shouldn't need as much). Also, the dowels are screwed on at both ends, not glued.If quiters never win, and winners never quit, who the heck came up with the idea that you should quit while your ahead?

maybe a better measure would be thickness. about 3/16"-1/4".If quiters never win, and winners never quit, who the heck came up with the idea that you should quit while your ahead?