im thimking about getting mugen wheels but can somebody explain the difference between 42mm and 50mm offset and how does it compare to the stock 45mm offset?

the lower the number of the offset, the more your wheel will stick out. usually more lip too.

king motorsports rec. the +50 but most racers and even the itrca rec. the +43...check out their wheel guide...itrca.com

The difference is 8 mm.

I believe the stock offset is actually 50 mm.

Offset is how far in or out the wheels stick. It's the lateral difference between (a) the mounting surface (the flat surface of the hub and of the inside of the wheel) and (b) the center of the wheel. Most FWD cars have more of the wheels surrounding the hub, which is called "positive offset" - the bigger the number, the more they're offset inwards toward the center of the car. Some cars (like "low riders") have negative offset - in which case the bigger the number, the more they stick out.

yes stock ITR wheels are 50 offset.....45 offset for JDM EK9 CTR...

The 50mm offset is probably there for the 5G Prelude guys. Not sure what size you are thinking about, as that will affect offset requirement as well as the width.

so is the itr 45 or 50 mm offset

it is +50 on both the USDM *and* JDM wheels.

yoshi - who'd show j00 pix, but I've already taken down my zing album

If you want to run 225s without rubbing get the 50mm offset.

the 43 mil offset will allow more space for bigger brake calipers, but you will be limited to a 215 section width tire unless you roll your fenders.

Holy $hit...I cant imagine how 225's would not hurt performance by a large degree. Thats an awful lot of rubber to move.

Not if you have 12 lb rims.

My Mugen MF-10s with Pirelli P7000s plus air weigh 26 lbs. I have trouble hooking up in 1st and 2nd gear - too light!