Too FS or not to FS

[outtafocus]

I picked up a brand new ZX-5 SP kit today on a smoking deal.
I thought it was an FS before I got to the shop but I was quite disappointed when I found it to be an SP version.

The deal was so good, I still bought the car.

Now my question is, do I spend the money and pick up the SP to FS conversion kit?
Effectively doubling the price of the car.

The racing in my area will not need the top of line equipment to be competitive, so really the SP will be fine. But its the I want it factor.

I dont own any saddle style Lipos, but do have a bunch of stick style.
So all buying the FS conversion will do is make me spend more money anyway.

Im new to the ZX-5 range and I dont really know what different on the FS. Is there any suspension geometry changes? Are most spares interchangeable between both cars? (well apart from chassis, braces and motor mount stuff)

Also on a side note, the same store has a RB5 SP buggy kit I can get for a steal to. Is this car worth picking up? I dont know anything about the RB5 versions, but have heard there is little different between the SP and SP2.

Thanks