Thanks a lot for your help.
Surely I will study your link.
Up till now I have visited various thread on internet
my problem is tu pull out the woofer. Space under CNG cylinder is 5". And I hardly able to pull it out
And if it will with the enclosure it was impossible.
So looking for something keh woofer ko nikaalnaa bhi easy rehay. And half enclosure
woofer kay sath ban jaye and half spare tyre mein.
Shallow mount may also be the solution, however looking for some other idea
if successful 