SR3 ownership queries

[gee_fin]

Afternoon all, I'm looking for some advice from owners if possible! I'm considering an SR3 for road/track use and have a couple of questions which would help me hugely on certain decisions...

Engines

What are the differences in running hours for the 200/250bhp Powertec options and how does road running affect these - ie. are the hours strict/absolute, or are they 'race' hours?

I'm considering all engine options, from standard, 200bhp, 1500/250bhp and non-factory turbo. To the point I would consider buying a standard engine for road use and Powertec for track use. I've a fair amount of experience with bike-engined cars in other marques but I'm coming into Radicals very green - are engine transplants straight-forward or absolute grief?

Fuel

The pump fuel I have available isn't the greatest (lower octane than the UK), although race gas is available (but not cheap!), are there any limitations/recommendations on the fuel for each engine?

Cooling

Are there any additional or recommended cooling options for running the SR3 in hotter climates? e.g. diff/transaxle coolers/etc?

Many thanks,
Graeme.