Hi Blackster,
Looking at purchasing a set of Flex myself, which have the same (7/6) spring rates.
From what I've read, with stock bars the car will be biased fairly heavily towards oversteer with these rates. Possible solutions are removing rear bar, installing larger front bar, both, or changing spring rates.
There is a really useful spreadsheet made by a bloke named Shaikh who makes suspension gear for Miatas in the US. You can plug in spring rates and roll bar settings a get a rough idea of how each will change the balance of the car. Here's the link:
http://www.fatcatmotorsports.com/FCM_MSDS_v7_5.xlsYou'll also want to convert kg/mm into lbs/in to use the spreadsheet - here's a link for that:
http://www.google.com.au/search?hl=en&q ... 2Fin&meta=I'd be really interested to hear opinions from people already running the 7/6 rates as to what they thought of them. I'm worried that they will be too stiff for street use and also too biased towards oversteer.
I'm considering running 6/4, 7/5 or 8/5 rates. It's really hard to make a decision without knowing what the car is going to ride like. My car really only gets drĂven on weekends and occasionally at night, but rarely for transport - it's mostly 'joy-riding'
I'd also like to do some track days, etc., but I don't want the car to be a (literal) pain in the bum as it will still spend 90+% of it's time on public roads.