Everyone has margins and everyone has costs. Costs covers everything from suppliers to rent to wages to other overheads. Dependent on those costs and dependent on what profit people want to/can make will set the margin i.e. cost of part from supplier plus other costs plus what profit can be made.
This applies across a business as a whole. What you are seeing at RossMods may not be the case across the whole of thier product line - it may be that they are pricing hard on 1/10th spare to get into a market which they havnt been as active in as JE - but they may be maintaining thier overall profitabilty across the whole business by upping/maintaining costs on other lines.
With a renewed RossMods clubs focus, new(ish) ecommerce website and social media presence, 1/10th "team" and trackside support at regionals/nationals and increased oople presence - I would say that the pricing is part of an overall expansion strategy into 1/10th off road. If sucessful you may see a flattening off on the 1/10th costs as they build a loyal base - but then its a very competative market!
For my money, JE Spares has the best ecommerce site in the market and the best social media strategy (discount codes via fb, twitter etc). That being said, RossMods overall strategy seems broader and more agressive.
Sorry for length of post - but I like this sort of stuff (its sort of my job!
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