First try to up the bore size and lower the stroke height instead of switching out the block, you should be looking at 88+ pistonsize and 81- pistonlength to get the best reliability to power ratio (i think i had something like 89 bore and 80 stroke on the 300hp engine) and constantly check towards rpm to find the sweetspot. And don’t forget to add qualitypoints.
When it comes to tuning the suspension you should (imo) aim for a straight line after the bump and rebound on both front and rear suspension, at a time when you have evened out the aero to (as close to) zero as possible, and then you dial in as much front and rear camber as you like and finetune with the swaybars to get the drivingprofile you like.
Use 265/30 - 35 tires both front and back (at least that’s my sweet spot, i think it’s depending on car type)
Be sure to check both low and high speed graphs, and the information on the testtrack tab. (Can post images of what i mean later)
And you should aim for balance between sportiness and driveability.