Renault 5 boxes dont take that sort of power on a trackday for long IME, dont think they are any stronger than the williams box TBH

Dont want N/A for big power as it means spending out loads of money on solid lifters etc just to see relatively small gains, turbo makes far more sense if Im going to get more power out of it.
Adding 50% more power (roughly what Id like to do) by N/A tuning is going to be massively expensive, like 5k+, and then i'll be on short pistons that dont last many miles etc too, its just not a good way of getting reasonable power from an engine