the 335xi comes with BMW's famousand intelligent xDrive rather than the normal AWD system in the 328xi, so i wanted to know what r the advantages of this xDrive in the 335xi when u compare it with the RWD 335i coupe?

Improved handling in general. There are things that a proffesional driver can do with a RWD car that cannot be done with AWD, but for an average skilled driver, AWD is better for safety and handling. Also, the difference between the AWD version and the RWD version is night and day when snow is involved. A RWD car with lot's of power, especially with a manual transmission is not a very good set up for winter driving. The AWD will make it easier to start from a stop, and help keep it in a straight line while driving. Not only is a nice safety feature, it is also a huuuuge convienence feature.

I recently got a 328i. I also test drove the 328ix. I have to admit that I was a little apprehensive about getting a rear wheel drive car, especially given how the old fashioned ones behaved in the winter weather. But I have to say, I am blown away by the ride and handling. I've not driven in snow or ice yet, but in some really horrible rain (can barely see where the road is kind of rain) the car would not budge an inch in terms of sliding or feeling unstable. In fact it felt better planted to the road than my previous car (Acura TL).

Now I have heard that if you get the sports package the tires are specifically designed for drier conditions, whereas the non-sport is more general purpose. So that may factor into your considerations.

If money were no object and/or I lived in an area with a lot of winter weather, which I don't, then I'd probably get the xdrive system for added safety. But so far the rear wheel drive has proven to be outstanding.

Any of them would be a great choice. The only difference is the xDrive. If you are looking at the coupe/sportscar segment, I'd also recommend an Infiniti G37 coupe:
http://www.infiniti.com/g_coupe/index.html

Good Luck.