Power to Weight is where its at for me.. and who drives at over 100mph on a regular basis

any way my dad is building mini with an 8V 1600 astra engine with 13inch wheels metro turbo brakes ect.
power wise looking at 90ish which dont sound a great deal, but the thing is soo low to the deck and going to have sooo much grip on the 13x7 inch rims it going to be sooo much fun to drive.
He has decided to do a Vtec next but they are MUCH more expensive a whole engine/car ect for the transplant cost more than this current one is costing i reckon