Yale, If you are an average sized ( or a bit larger ) person, you can handle a Scrambler easily. If you're a "little person" you may want to look at the ex. If your riding involves mud, get the Scrambler. If your only going to ride it in the dunes or on an MX track, or wide open areas where you don't NEED REVERSE, get the ex. If you ride in tight areas where getting off of the quad and LIFTING IT UP AND TURNING THE QUAD AROUND BY HAND would seem to be a pain in the a$$, get the Scambler.
I have a rear rack on my 2000 400 Scram 2X4,and have carried 150lbs of feed on it without a problem.
Put a clutch kit in the Scrambler, and it's a whole different animal.

 

The owner re-jetted the 400EX because he did the muffler and the air box mods/K&N filter all at the same time. John

 

emptytank-

Anytime you change your airflow (slip on pipe) you MUST rejet to get the full benifits. So yes, rejet a size or two bigger. - and remove that air box lid and throw on a K&N filter w/ outerware.

 

UUUmmmm ya ok if your going to be on rough trails the last thing i would recomend would be the polarbus , my friends dad has one and we were riding with a cr80 set up for MX a stock blaster a stock recon and the mighty scambler 400 , well the polarbus was always at the back of the pack and where the blaster dirtbike and recon went accrosss the mud the 4X4 polarbus gut stuck . he got stuck like 5 times and we got stuck ounce . the polarbus through him around like a sally and even his father gets sick of its wobbaly steering . polarbus sucks in my opinion ! get the 400ex unless you like crappy handling and arent afffraid of heights !

 

They are full of it!
I rejetted after I installed a wb slip on my 400ex, These things run lean from the factory, and if you are increasing air flow like they claim you will and do to get more spunk then well it dont take a rocket scientist to figure you need more fuel.....
I run a 160 main, 4th notch on the needle, and a 42 pilot jet. 2- 1 1/2 holes in air box lid, stock air filter, and if anything im still to lean.

 

Here's what I've found driving scramblers. On little jarring bumps, pot holes, and ripples(from skidder tires) the polaris is much less harsh than my 400ex. Soft suspension, great for trail riding. Whoops and jumps the 400ex has way faster rebound( especially front shocks) and It is better for that stuff. the scrambler feels like you're out of controll when cornering fast. Up high and tippy. the Ex is low slung and rails the corners, or powerslides.

Power is suprising on the scrambler(the "X" modle) picks up fast down low. May be lower gearing than the regular scramblers. when I drag my dad (me on my 400ex, him on the scrambler) it seems to be dead even through the first 3 gears. I could always beat his 99' sport 400 right from the start to finish, but the 500 has good low end. now say you're going 30-50 mph, and you nail it! The scrambler feels slushy compared to my stock 400ex. the ex pulls hard and revs out fully and fast compared to the scrambler. it walks away when you are at speed and peg the throttle.

If you are in it for maximum comfort and want to just trail ride, the scrambler would be a good choice. You can still play around on it but it is not as much fun as the EX. the 400ex is a do it all bike. Fairly comfortable on long trail rides(but after a long day, the suspension seems harsh compared to the super plush/mushy scrambler suspension) you can race it, play around on it, and do anything but utility work, and technicle rough trails. the ex will requier less maintnance as well(no greese fittings, and longer bearing and bushing wear mainly because it's 150lbs lighter-less stress on components)

 

Actually to build a 505 it costs the same as to build a 440. Go check out sparksracing.com .
I have drag raced a piped and clutched 400 sport and its front wheels were even with my back wheels. thats not too bad. but some of these guy's 400 sports on this forum are extremely fast, but i am almost sure that even just a 465 would beat some of them, due to power:weight, rider weight.