I have no clue who starred in the film it was a comedy, and it may not even be a British film... came out perhaps 80's or 90's

It was 2 men detectives, that were
always fighting.... and there was a scene they were dressed as monks and
started fighting and the nuns were all upset and passed out cause there were
fighting.

Then in another scene...they got into a Ferrari and drove and the car was
going so fast that when he drove past some people it took their clothes
off...

Now please where I can find the name of the movie and possibly can download the movie

Just tried searching google and found the following movie:

Dectective School Dropouts (1986)

"They start off by posing as tourists with Japanese names after lifting the boarding passes from two unsuspecting Japanese passengers, to foul play aboard an Italy-bound airliner, to the hi-jinx in a Rome museum, masquerading as monks in the Vatican to the nerve-shaking Ferrari escapade....never a dull moment!!"

Sounds like a good match

Never heard of it, but you won't find any links or hints of where to download it on here, due to it being piracy related.

May be you can try moonlightcinemanetworks.com. It has a large collection of movies. Please see if you get the answer of your question. Possibly NUNS ON THE RUN but as I haven’t seen the movie I can’t be sure.