Hi craig
bite the bullet and put a big sump in to begin with,ihave a r32gtr [320 plus 4wkw] that i use at club days and have shit 2 motors due to oil issues or the lack of it.
a boosted gtr motor even with a restrictor in the oil gallery pumps about 2.5litres into the head and that leaves bugga all in the sump.
Man i have tried the tommie sump unit and others,at the moment i have the tommie system and a 20mm oil return line direct to the sump and every thing is going well with hill climnbs,motorkana's and autocrosses,havn't done any more club days though.[don't want to wreck another motor].
stuart